New partner is to be revealed (9)
I believe the answer is:
transpire
'be revealed' is the definition.
(I've seen this before)
'new partner is' is the wordplay.
'new' indicates an anagram.
'partner'+'is'='partneris'
'partneris' anagrammed gives 'TRANSPIRE'.
'to' acts as a link.
(Other definitions for transpire that I've seen before include "Come to pass" , "Lose water vapour" , "Turn out" , "Terrapins (anag)" , "Ensue with terrapins" .)