Sometimes in a fight after "locking on" an enemy I can't seem to find a way to "unlock" . I tried the same button and that doesn't work. I've also looked under the controls menu and only see "lock on" but no way to unlock. probably something obvious but i sure don't see it thanks for any help.

Use the "sheathe weapon" button ([Page Down] by default). Despite the label, when you're locked on, it will unlock you first rather than sheathe the weapon (which only happens if you're not locked.)

That's it!! thank you for the help.