How do you service air conditioning on a 2007 pacifica?

Well, there's a couple things to consider here.

First off, what type of service are you trying to perform? Second off, servicing an AC system is not a DIY task - without any offense intended, if you can't even specify what it is you're trying to do exactly, it's highly unlikely you'd know what you were doing once you started working on an AC system, and this is further reinforced by your asking this question on here.

My advice would be to have a certified tech do it. Yes, we all hate spending money on these things, but you'll be spending a lot more later on the replace AC system components than to have it done the right way now.