You can try below ways to unlock the file:
tf lock /lock: none
Please see Lock Command for details:
To use the lock command, you must have the Lock permission set to Allow. Having the Unlock other user's changes permission set to Allow is required to remove a lock held by another user if you do not have Write permission for that user's workspace
tf lock /lock:none /workspace:workspacename [/recursive][/login:username,[password]] [/collection:TeamProjectCollectionUrl]
tf undo
The undo command removes any locks on the items. See Undo command
To unlock individual files run the command below in Visual Studio Command Prompt:
tf undo "file_path" /workspace:workspace_name
e.g.:
tf undo $/S/B/ABC/dotNET/Symphony/Tools/xyz/abc/Abc.dll /workspace:Houst01
here it will unlock Abc.dll which is inside abc folder.
To unlock the whole folder in one shot:
tf undo $/S/B/ABC/dotNET/Symphony/Tools/xyz/abc/* /workspace:Houst01
here it will unlock all files which is inside abc folder.