Easy Vertex EVX-534 Question for Somebody

I have an Vertex EVX-534. I turn on scan by pressing the “A” button. How do I turn on “Priority Scan”? It used to be one, but somehow it got turned off. Please help.

The A, B, C, and D buttons are programmable, so the buttons to press for various scan functions will depend on how your particular radio was programmed. You may need to contact who ever programmed your EVX-534 to determine which button is set for priority scan.