Learnt to change regular payment (6)
I believe the answer is:
rental
'regular payment' is the definition.
(rent payments)
'learnt to change' is the wordplay.
'to change' indicates anagramming the letters.
'learnt' with letters rearranged gives 'RENTAL'.
(Other definitions for rental that I've seen before include "Something paid for hire" , "Hire charge" , "Hire fee" , "Learnt (anag) -- lease" , "Amount paid for hire" .)