Sally rejoins Tories (6)
I believe the answer is:
sortie
'sally' is the definition.
(I know that sally can be written as sortie)
'rejoins tories' is the wordplay.
'rejoins' indicates anagramming the letters.
'tories' with letters rearranged gives 'SORTIE'.
(Other definitions for sortie that I've seen before include "Sally" , "Operational flight by a bomber or fighter" , "Military raid" , "Attack by a besieged garrison" , "Single military flight" .)