1997 Plymouth Voyager A/C low pressure switch. Easy to fin

AC will run and cools just fine. But, if I stop and park the car for a while 80% of the time AC will not cool once I start back up. It will also go out if I idle for a while (Like at a drive thru or stop and go traffic) All fans blow fine. I have been narrowing down my AC problem over the last week. I had the shop look at it, they did a freon evac and replace but could not replicate the above problem. It continues to be an off and on thing. I have decided it is a bad low A/C pressure switch. Freon is okay-A/C Clutch and components OK too-Car not overheating. What is involved in replacing the low pressure switch and is it something I could do?