Morse changing name and address (6)
I believe the answer is:
sermon
'address' is the definition.
(I know that sermon is a type of address)
'morse changing name' is the wordplay.
'changing' is an anagram indicator.
'name' becomes 'n' (common abbreviation e.g. on forms).
'morse' with letters rearranged gives 'sermo'.
'sermo'+'n'='SERMON'
'and' acts as a link.
(Other definitions for sermon that I've seen before include "Moralising address from pulpit" , "Moralising lecture" , "Moralising oration" , "Lecture from a pulpit" , "Address given weekly" .)