A thing done cannot be undone.

Explanation

Once an act is completed — a deed delivered, an instrument executed — the actor cannot recall it by his own will alone.

Where this applies

• I signed the deed and delivered it — I can't just take it back now.
• Once the instrument is executed and delivered, the actor can't unilaterally recall it.
• They want to undo a completed transaction but it's too late — what's done is done.

See also

• 5.2.4 Land lying unoccupied is given to the first occupant.
• 11.2.5 Bad grammar does not vitiate a deed.