Choose new top (3)
I believe the answer is:
opt
'choose' is the definition.
(both can mean to pick something)
'new top' is the wordplay.
'new' indicates anagramming the letters.
'top' is an anagram of 'OPT'.
(Other definitions for opt that I've seen before include "Prefer, choose" , "Decide between possibilities, choose" , "Elect" , "End or act of shutting" , "Make a choice" .)