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 an anagram.
'top' anagrammed gives '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" .)