We are just starting to use InCopy at our office and the question has come up--what if someone checks something out, forgets to check it back in, then leaves on vacation? Is there a way for someone else to check it back in? We use laptops here so we would not have access to the hypothetical person's computer. Thanks!
The easiest way around that would be to unlink the InCopy content and then re-export it.
What Bob said, or someone can change their username temporarily (File > User) to match the vacationer's, and then check it in for her/him.
You can only change your username when you don't have any checked out stories in the active layout, so best to do that with no files open in InDesign or InCopy (either one can do the job).
Best practice is to check in your stories at the end of the day, simplest way to do that is to close all your files and let InCopy check them in/save them for you (you'll see the prompt offering to do so).