It will be because they are being shared. What you can do is temporarily unshare them, change their name & then reshare them. How to do ... in the Library window, right-click on the file & choose stop sharing. Then change name & then right-click again to share again. You'll know if they are being shared or not because files that aren't being shared are red.

However, if someone "is" uploading the file, then it would be fairer to let them finish uploading it 1st which shouldn't take very long. You can check by viewing the monitor window. Otherwise if you change the name it may also change the hash of the file so they would not be able to re-continue uploading the file to finish it.