In Freshservice, you can notify the requester about a change in ticket priority by setting up an automation rule by following the steps below.

  1. Navigate to Admin > Automation & Productivity > Automation > Workflow Automator-->New automaton. 
  2. Choose the Event based automator option.
  3. Set the Event as Priority is changed from Any to Any. 
  4. Add an action block, choose the action as Send email to Requester, and provide the email notification that must be triggered to the requester.
  5. Activate the rule.

    Notifying the requester about a change in ticket priority.