Change later, perhaps (5)
I believe the answer is:
alter
'change' is the definition.
(I know that change can be written as alter)
'later perhaps' is the wordplay.
'perhaps' indicates anagramming the letters.
'later' with letters rearranged gives 'ALTER'.
(Other definitions for alter that I've seen before include "reform" , "and 10 Across: Second self" , "Vary" , "Amend" , "Change, maybe later" .)