Former college to change, introducing degrees (4,5)
I believe the answer is:
alma mater
'former college' is the definition.
(I've seen this before)
'change introducing degrees' is the wordplay.
'change' becomes 'alter' (synonyms).
'introducing' is an insertion indicator (some letters introduced or inserted into others).
'degrees' becomes 'MA MA' (two abbreviations for Master of Arts degree).
'alter' enclosing 'mama' is 'ALMA MATER'.
'to' acts as a link.
(Other definitions for alma mater that I've seen before include "Alert mama to the old school" , "College one attended" , "originally taught here?" , "College from which one has graduated" , "One's place of education" .)