I have a process model. Is there a way that if I cancel a task in that process

How did you achieve this mikec? 
Can you please share how were you able to identify when the task is cancelled to be able to set your process variable (pv!cancel) to true.? (Referring to this part : "On the output of the task if not cancelled then set the value to False.")

Appreciate your response. Thanks.

I believe what has been discussed involves creating a buttonWidget (set submit to true) in the interface that saves true() into a boolean ri value e.g. ri!cancel. This value would then be mapped to a pv in the process model which will be processed by an XOR to determine the appropriate process flow.

Hey John Pang, thanks for your response but I did not get you. I am asking how about how exactly do we check that the task is cancelled to send out pv!cancel = true in the output? Since the user is not cancelling it, it is being cancelled from another process.

Let me check if I'm understanding you correctly, you want to cancel a process instance where a task is being cancelled by another process?

Yes.

Could you elaborate on your use case? 

Sure. I have a process model. I want to cancel a task in that process model (from another Process model). I am able to do this but I also want to trigger to cancel the process instance (with that task)? Hope it is clearer...