Cannot remove old server

You will need to be more specific - the question as it stands is too vague to permit an answer.

I don't think his question is too vague -- it seems spot on to me.

Where are good instructions on dealing with a removed server?

Here is a specific example -- user decides to quit using Apple Server. After removing Apple Server the server printers are still around (how do you get rid of "communication error" and how do you get re-connection to the printers?) How do you get rid of the myriad of references to the old, now non-existent server (such as the the "Connect [name of now non-existent VPN]"). There must be some comprehensive technical note to describe what to do to remove all the residual references and connections to the now removed Server.

To be even more specific -- when a person attempts to use another machine as their server, how do you get rid of the server on the first machine?