I'm working on a couple of assumptions here that are:-
1 - you can't just delete the linked server and put it back if necessary
2 - the connections are made through the linked server via either a standard login or by a user login
If they are both correct, can you go into the security tab of the linked server properties and select the top radio button (also assuming there are no mappings in the top box)?
That way, you can always put it back quicker than having to relink the servers.