There are two questions here, and I am not sure which one you are asking.
1. Can I move my existing .pc3 files from one network location to another, and make autocad see them?
2. Can I change my existing .pc3 files to point to a new printer (same device, shared from a new server)
The answer to #1 is YES, in fact it's not terribly hard - pc3s are just files, copy them to a new location, and change the Printer Configuration Search Path in everyones profile.
The answer to number 2 is SOMETIMES. As David Allen notes, sometimes you can browse the ports, and redirect the .pc3 to a different device, sometimes you can't. I think the difference is a function of the specific printer driver you are using, but I've never spent the time really diagnosing this - building a new .pc3 is a simple task.