Get old and incorrect schedule (6)
I believe the answer is:
agenda
'schedule' is the definition.
('agenda' can be a synonym of 'schedule')
'get old and incorrect' is the wordplay.
'get old' becomes 'age' ('age' can be a synonym of 'get old').
'incorrect' indicates an anagram.
'and' with letters rearranged gives 'nda'.
'age'+'nda'='AGENDA'
(Other definitions for agenda that I've seen before include "List of things to be done or discussed" , "Schedule - things to be done" , "things still to be done" , "Programme of a meeting" , "List of items for discussion by committee" .)