How can i change task name dynamically ? and store to variable .

Let say ,

i create one task " request for computer " no it go to approval , when aprroval reject that request . i want to change "request for computer " task to " update request" . and assigned to requester again , i don't want to add another task "update request" in diagram . i just change the name of task dynamically is it possible ? or should i go to diagram specific and add two task one for approve and other for update