His girlfriend has thrown him out and has changed the locks on the door so he cannot get into his own flat.
POSITIVELY FEARLESS: Breaking free of the fears that hold you back (2001)
Your daughter can't just force her way into the house and change the locks.
The Sun (2015)
The survey also found two thirds of people failed to change the locks when they moved into a new home.
The Sun (2012)
Definition of 'lock'
lock
(lɒk)Explore 'lock' in the dictionary
countable noun
The lock on something such as a door or a drawer is the device which is used to keep it shut and prevent other people from opening it. Locks are opened with a key.