Answer:

undid

Answer	Crossword Clue
UNDID	Canceled
UNDID	Annulled
UNDID	Used the backspacer

UNDID	Canceled out
UNDID	Loosened
UNDID	Took apart
UNDID	Nullified
UNDID	Reversed
UNDID	Erased
UNDID	Opened
UNDID	Voided

UNDID	Reversed the effects of
UNDID	Fixed a word-processing error
UNDID	Erased, in a way
UNDID	Opened, as a blouse
UNDID	Brought to naught
UNDID	Reversed, as an action
UNDID	Ruined
UNDID	Took back

UNDID	Destroyed
UNDID	Took back, in a way
UNDID	Opened, as a knot
UNDID	Opened, as a tie
UNDID	Opened, as a necktie
UNDID	Opened.
UNDID	Loosed.
UNDID	Brought to naught.

UNDID	Brought to ruin.
UNDID	Annulled.
UNDID	Nullified.
UNDID	Spoiled.
UNDID	Disengaged
UNDID	Disassembled
UNDID	Loosened a knot
UNDID	Loosened, as a knot

UNDID	Disconnected
UNDID	Disentangled
UNDID	Reversed an action
UNDID	Detached
UNDID	Dealt a severe blow