Key in again (6)
I believe the answer is:
retype
'key in again' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for retype that I've seen before include "Set (the same text) again on a word processor" , "Produce document again" , "Repeat work in pool" , "impress again" , "Put into printed characters again" .)