If you take apart an existing PEX connection, is it going to perform correctly if you re-crimp the same end of the tube - without cutting it - to a new fitting?
Often with PEX you can flex it a bit and get a little more length, and probably if that is the case you should cut a fresh end. But if you really have NO additional length to work with... would this work?
Assume that the tube end isn't damaged while removing it from the original fitting (which can be difficult). A really warped, cut, or otherwise mangled pipe end may pose a greater risk and isn't what I'm really thinking of. That said, even a carefully removed tube will have some distortion from the barbs it was pressed into.