Have another go at reforming Terry (5)
I believe the answer is:
retry
'have another go' is the definition.
(I've seen this before)
'reforming terry' is the wordplay.
'reforming' indicates an anagram.
'terry' is an anagram of 'RETRY'.
'at' acts as a link.
(Other definitions for retry that I've seen before include "Hear (a case) again" , "Have another go" , "Make a further attempt" , "take second opinion on case" , "Advice following failure, initially" .)