MD5 to DES encryption

Is it possible to change the type of encryption from MD5 to DES without removing a user?

Way back when this server was created, users were created with the MD5 encryption. Now, all users created with DES encryption. Is it possible to just change the type of password encryption? Users using the MD5 encryption are experiencing problems logging onto some machines that DES users log onto with ease.

Thanks.

Remove the line from /etc/passwd and re-create it using your new process? You don't have to delete any of their files (just be sure to use the same UID)