If you didn't find the commands to remove a file lock, here they are:
# isi_for_array 'isi smb openfiles list'
Optionally, you can grep for part of the file/filename.
Once you have the ID, you can run:
# isi_for_array 'isi smb openfiles close --id=[##########] --force'
I've also had to run the command to kill a user's sessions if the file close didn't do the trick.
# isi_for_array 'isi smb sessions list'
Again, you can grep for a specific username, if it helps.
# isi_for_array 'isi smb sessions delete --computer-name=[IP] --force'
You can kill SMB sessions via user, but I've not had as much luck with it.
# isi_for_array 'isi smb sessions delete-user --[user/sid/uid]=[usernamed/sid/uid]'
Hope this helps!