Index: lams_tool_scratchie/conf/language/lams/ApplicationResources.properties
===================================================================
diff -u -r0b845931db55d90f0dcabc0b33cce5c7df688153 -r281e19ba98aa6bf38fc1f25507a9098304d668fb
--- lams_tool_scratchie/conf/language/lams/ApplicationResources.properties	(.../ApplicationResources.properties)	(revision 0b845931db55d90f0dcabc0b33cce5c7df688153)
+++ lams_tool_scratchie/conf/language/lams/ApplicationResources.properties	(.../ApplicationResources.properties)	(revision 281e19ba98aa6bf38fc1f25507a9098304d668fb)
@@ -61,6 +61,9 @@
 label.monitoring.summary.date = Date
 label.monitoring.summary.report.for = Report for {0}
 label.monitoring.summary.choose = Choose...
+label.monitoring.change.leader = Change leader
+label.monitoring.leader.successfully.changed = Leader changed
+label.monitoring.leader.not.changed = Leader was not changed
 label.monitoring.item.summary.group = Group:
 output.desc.learner.mark = Total mark scored by learner
 warning.msg.authoring.do.you.want.to.delete = Do you really want to delete this question?
Index: lams_tool_scratchie/src/java/org/lamsfoundation/lams/tool/scratchie/dto/GroupSummary.java
===================================================================
diff -u -r3a4e0fbc4b00ff567f1dc7561cf9596fedab7c8e -r281e19ba98aa6bf38fc1f25507a9098304d668fb
--- lams_tool_scratchie/src/java/org/lamsfoundation/lams/tool/scratchie/dto/GroupSummary.java	(.../GroupSummary.java)	(revision 3a4e0fbc4b00ff567f1dc7561cf9596fedab7c8e)
+++ lams_tool_scratchie/src/java/org/lamsfoundation/lams/tool/scratchie/dto/GroupSummary.java	(.../GroupSummary.java)	(revision 281e19ba98aa6bf38fc1f25507a9098304d668fb)
@@ -35,6 +35,7 @@
     private int totalAttempts;
     private String totalPercentage;
     private Long leaderUid;
+    private boolean scratchingFinished;
 
     //used for itemSummary page
     private int numberColumns;
@@ -118,6 +119,14 @@
 	this.leaderUid = leaderUid;
     }
 
+    public boolean isScratchingFinished() {
+	return scratchingFinished;
+    }
+
+    public void setScratchingFinished(boolean scratchingFinished) {
+	this.scratchingFinished = scratchingFinished;
+    }
+
     public Collection<ScratchieUser> getUsers() {
 	return users;
     }
Index: lams_tool_scratchie/src/java/org/lamsfoundation/lams/tool/scratchie/service/IScratchieService.java
===================================================================
diff -u -r5aabc63ac1eb20bb16e7b586981129b3208323e3 -r281e19ba98aa6bf38fc1f25507a9098304d668fb
--- lams_tool_scratchie/src/java/org/lamsfoundation/lams/tool/scratchie/service/IScratchieService.java	(.../IScratchieService.java)	(revision 5aabc63ac1eb20bb16e7b586981129b3208323e3)
+++ lams_tool_scratchie/src/java/org/lamsfoundation/lams/tool/scratchie/service/IScratchieService.java	(.../IScratchieService.java)	(revision 281e19ba98aa6bf38fc1f25507a9098304d668fb)
@@ -455,4 +455,6 @@
     Map<String, Object> prepareStudentChoicesData(Scratchie scratchie);
 
     boolean isLearnerEligibleForMark(long learnerId, long toolContentId);
+
+    void changeLeaderForGroup(long toolSessionId, long leaderUserId);
 }
Index: lams_tool_scratchie/src/java/org/lamsfoundation/lams/tool/scratchie/service/ScratchieServiceImpl.java
===================================================================
diff -u -r0b845931db55d90f0dcabc0b33cce5c7df688153 -r281e19ba98aa6bf38fc1f25507a9098304d668fb
--- lams_tool_scratchie/src/java/org/lamsfoundation/lams/tool/scratchie/service/ScratchieServiceImpl.java	(.../ScratchieServiceImpl.java)	(revision 0b845931db55d90f0dcabc0b33cce5c7df688153)
+++ lams_tool_scratchie/src/java/org/lamsfoundation/lams/tool/scratchie/service/ScratchieServiceImpl.java	(.../ScratchieServiceImpl.java)	(revision 281e19ba98aa6bf38fc1f25507a9098304d668fb)
@@ -24,6 +24,7 @@
 package org.lamsfoundation.lams.tool.scratchie.service;
 
 import java.io.IOException;
+import java.security.InvalidParameterException;
 import java.sql.Timestamp;
 import java.text.SimpleDateFormat;
 import java.util.ArrayList;
@@ -118,6 +119,7 @@
 
 import com.fasterxml.jackson.databind.JsonNode;
 import com.fasterxml.jackson.databind.node.ArrayNode;
+import com.fasterxml.jackson.databind.node.JsonNodeFactory;
 import com.fasterxml.jackson.databind.node.ObjectNode;
 
 /**
@@ -722,6 +724,8 @@
 	    // one new summary for one session.
 	    GroupSummary groupSummary = new GroupSummary(session);
 
+	    groupSummary.setScratchingFinished(session.isScratchingFinished());
+
 	    int totalAttempts = scratchieAnswerVisitDao.getLogCountTotal(sessionId);
 	    groupSummary.setTotalAttempts(totalAttempts);
 
@@ -2216,6 +2220,38 @@
 	}
     }
 
+    @Override
+    public void changeLeaderForGroup(long toolSessionId, long leaderUserId) {
+	ScratchieSession session = getScratchieSessionBySessionId(toolSessionId);
+	if (session.isScratchingFinished()) {
+	    throw new InvalidParameterException("Attempting to assing a new leader with user ID " + leaderUserId
+		    + " to a finished session wtih ID " + toolSessionId);
+	}
+
+	ScratchieUser existingLeader = session.getGroupLeader();
+	if (existingLeader == null || existingLeader.getUserId().equals(leaderUserId)) {
+	    return;
+	}
+	Scratchie scratchie = session.getScratchie();
+	ScratchieUser newLeader = getUserByUserIDAndContentID(leaderUserId, scratchie.getContentId());
+	if (newLeader == null) {
+	    return;
+	}
+	if (!newLeader.getSession().getSessionId().equals(toolSessionId)) {
+	    throw new InvalidParameterException("User with ID " + leaderUserId + " belongs to session with ID "
+		    + newLeader.getSession().getSessionId() + " and not to session with ID " + toolSessionId);
+	}
+
+	session.setGroupLeader(newLeader);
+	scratchieSessionDao.update(session);
+
+	Set<Integer> userIds = getUsersBySession(toolSessionId).stream()
+		.collect(Collectors.mapping(scratchieUser -> scratchieUser.getUserId().intValue(), Collectors.toSet()));
+
+	ObjectNode jsonCommand = JsonNodeFactory.instance.objectNode();
+	jsonCommand.put("hookTrigger", "scratchie-leader-change-refresh-" + toolSessionId);
+	learnerService.createCommandForLearners(scratchie.getContentId(), userIds, jsonCommand.toString());
+    }
     // *****************************************************************************
     // set methods for Spring Bean
     // *****************************************************************************
Index: lams_tool_scratchie/src/java/org/lamsfoundation/lams/tool/scratchie/web/controller/MonitoringController.java
===================================================================
diff -u -re743566518bd5c53d6574987565cfb8581a92c66 -r281e19ba98aa6bf38fc1f25507a9098304d668fb
--- lams_tool_scratchie/src/java/org/lamsfoundation/lams/tool/scratchie/web/controller/MonitoringController.java	(.../MonitoringController.java)	(revision e743566518bd5c53d6574987565cfb8581a92c66)
+++ lams_tool_scratchie/src/java/org/lamsfoundation/lams/tool/scratchie/web/controller/MonitoringController.java	(.../MonitoringController.java)	(revision 281e19ba98aa6bf38fc1f25507a9098304d668fb)
@@ -73,6 +73,7 @@
 import org.springframework.ui.Model;
 import org.springframework.web.bind.annotation.RequestMapping;
 import org.springframework.web.bind.annotation.RequestMethod;
+import org.springframework.web.bind.annotation.RequestParam;
 import org.springframework.web.bind.annotation.ResponseBody;
 import org.springframework.web.bind.annotation.ResponseStatus;
 
@@ -296,6 +297,14 @@
 	return "pages/monitoring/parts/statisticpart";
     }
 
+    @RequestMapping(path = "/changeLeaderForGroup", method = RequestMethod.POST)
+    @ResponseBody
+    @ResponseStatus(HttpStatus.OK)
+    private void changeLeaderForGroup(@RequestParam(name = AttributeNames.PARAM_TOOL_SESSION_ID) long toolSessionId,
+	    @RequestParam long leaderUserId) {
+	scratchieService.changeLeaderForGroup(toolSessionId, leaderUserId);
+    }
+
     @SuppressWarnings("unchecked")
     private SessionMap<String, Object> getSessionMap(HttpServletRequest request) {
 	String sessionMapID = request.getParameter(ScratchieConstants.ATTR_SESSION_MAP_ID);
Index: lams_tool_scratchie/web/pages/learning/learning.jsp
===================================================================
diff -u -r31c0a35b614dd390e386a617cc85827c4d00de47 -r281e19ba98aa6bf38fc1f25507a9098304d668fb
--- lams_tool_scratchie/web/pages/learning/learning.jsp	(.../learning.jsp)	(revision 31c0a35b614dd390e386a617cc85827c4d00de47)
+++ lams_tool_scratchie/web/pages/learning/learning.jsp	(.../learning.jsp)	(revision 281e19ba98aa6bf38fc1f25507a9098304d668fb)
@@ -82,6 +82,17 @@
 					etherpadInitMethods[groupId]();
 				}
 			});
+
+			<%-- Connect to command websocket only if it is learner UI --%>
+			<c:if test="${mode == 'learner'}">
+				// command websocket stuff for refreshing
+				// trigger is an unique ID of page and action that command websocket code in Page.tag recognises
+				commandWebsocketHookTrigger = 'scratchie-leader-change-refresh-${toolSessionID}';
+				// if the trigger is recognised, the following action occurs
+				commandWebsocketHook = function() {
+					location.reload();
+				};
+			</c:if>
 		});
 
 		//scratch image (used by both scratchMcq() and scratchVsa())
Index: lams_tool_scratchie/web/pages/monitoring/summary.jsp
===================================================================
diff -u -re743566518bd5c53d6574987565cfb8581a92c66 -r281e19ba98aa6bf38fc1f25507a9098304d668fb
--- lams_tool_scratchie/web/pages/monitoring/summary.jsp	(.../summary.jsp)	(revision e743566518bd5c53d6574987565cfb8581a92c66)
+++ lams_tool_scratchie/web/pages/monitoring/summary.jsp	(.../summary.jsp)	(revision 281e19ba98aa6bf38fc1f25507a9098304d668fb)
@@ -285,6 +285,37 @@
 		var url = "<c:url value='/monitoring/exportExcel.do'/>?<csrf:token/>&sessionMapID=${sessionMapID}&reqID=" + (new Date()).getTime();
 		return downloadFile(url, 'messageArea_Busy', '<fmt:message key="label.summary.downloaded"/>', 'messageArea', 'btn-disable-on-submit');
 	};
+
+	function showChangeLeaderModal(toolSessionId) {
+		$('#change-leader-modals').empty()
+		.load('<lams:LAMSURL/>tool/lalead11/monitoring/displayChangeLeaderForGroupDialogFromActivity.do',{
+			toolSessionId : toolSessionId
+		});
+	}
+
+	function onChangeLeaderCallback(response, leaderUserId, toolSessionId){
+        if (response.isSuccessful) {
+            $.ajax({
+    			'url' : '<c:url value="/monitoring/changeLeaderForGroup.do"/>',
+    			'type': 'post',
+    			'cache' : 'false',
+    			'data': {
+    				'toolSessionID' : toolSessionId,
+    				'leaderUserId' : leaderUserId,
+    				'<csrf:tokenname/>' : '<csrf:tokenvalue/>'
+    			},
+    			success : function(){
+    				alert("<fmt:message key='label.monitoring.leader.successfully.changed'/>");
+    			},
+    			error : function(){
+    				alert("<fmt:message key='label.monitoring.leader.not.changed'/>");
+        		}
+            });
+        	
+		} else {
+			alert("<fmt:message key='label.monitoring.leader.not.changed'/>");
+		}
+	}
 	
 	// pass settings to monitorToolSummaryAdvanced.js
 	var submissionDeadlineSettings = {
@@ -360,6 +391,12 @@
 					aria-expanded="${status.first ? 'false' : 'true'}" aria-controls="collapse${summary.sessionId}" >
 				${summaryTitle}</a>
 			</span>
+			<c:if test="${fn:length(summary.users) > 0 and not summary.scratchingFinished}">
+				<button type="button" class="btn btn-default btn-xs pull-right"
+						onClick="javascript:showChangeLeaderModal(${summary.sessionId})">
+					<fmt:message key='label.monitoring.change.leader'/>
+				</button>
+			</c:if>
         </div>
         
         <div id="collapse${summary.sessionId}" class="panel-collapse collapse ${status.first ? 'in' : ''}" role="tabpanel" aria-labelledby="heading${summary.sessionId}">
@@ -430,3 +467,5 @@
 <%@ include file="parts/advanceOptions.jsp"%>
 
 <%@ include file="parts/dateRestriction.jsp"%>
+
+<div id="change-leader-modals"></div>
\ No newline at end of file