Break a promise in reversing the general pact (6)
I believe the answer is:
renege
'break a promise' is the definition.
(I've seen this in another clue)
'in reversing the general pact' is the wordplay.
'reversing' is a reversal indicator.
'in' says the answer is hidden in the clue.
'egener' can be found hidden inside 'the general pact'.
'egener' written backwards gives 'RENEGE'.
(Other definitions for renege that I've seen before include "Don't follow suit when you can" , "Withdraw" , "In card games, revoke" , "South American cowboy" , "Default" .)