I have a file that is locked/checked out exclusively by a user who is no longer with the company. I need to make changes and want to know how to "steal the lock".
Ask your perforce admin to remove the lock by issuing
p4 unlock -f <file>
PS: To reuse the departed user's license, your perforce admin might also want clean up the files left opened by him. He can revert the pending edits if they are useless or transfer them to another user via "p4 reopen".
The "reopen" and "revert after reopen" can also be performed by ordinary users.