public Void execute(CommandContext commandContext) {
// check that the new process definition is just another version of the same
// process definition that the process instance is using
ExecutionManager executionManager = commandContext.getExecutionManager();
ExecutionEntity processInstance = executionManager.findExecutionById(processInstanceId);
if (processInstance == null) {
throw new ActivitiException("No process instance found for id = '" + processInstanceId + "'.");
} else if (!processInstance.isProcessInstance()) {
throw new ActivitiException(
"A process instance id is required, but the provided id " +