Can Requester change priority, or initiate escalation process

Can Requester change priority, or initiate escalation process

I'm looking for a way for a requester to escalate either the priority of a case.  It would be nice if the requester could just go into their ticket and change the priority with the technician then being notified. If that functionality doesn't exist is there some way I could use a business rule to mimic this?  so the user would respond to an incident/request with a phrase to trigger the priority change?  Has anyone run into this before?

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