update the statuscode

try
{
trace.Trace("inside try");
Entity target = (Entity)context.InputParameters["target"];
//retrieve
Entity entity = service.Retrieve("task", target.Id, new ColumnSet(true));
//pointer
EntityReference regardingCaseRef = entity["regardingobjectid"] as EntityReference;
Entity regardingCase = service.Retrieve(regardingCaseRef.LogicalName, regardingCaseRef.Id, new ColumnSet(true));
//retrieve multiple using query expression
QueryExpression qeRelatedTasks = new QueryExpression("task");
qeRelatedTasks.ColumnSet = new ColumnSet(true);
qeRelatedTasks.Criteria.AddCondition(new ConditionExpression("regardingobjectid", ConditionOperator.Equal, regardingCaseRef.Id));
EntityCollection relatedTasks = service.RetrieveMultiple(qeRelatedTasks);
trace.Trace("updatestatuscode");
if (AllTaskReject(relatedTasks))

{
Hi im new to crm how can i update the status code of the incident