Church with no end of incense for convert (6)
I believe the answer is:
change
'convert' is the definition.
('change' can be a synonym of 'convert')
'church with no end of incense' is the wordplay.
'church' becomes 'ch' (common abbreviation).
'with no end of' means to remove the last letter.
'incense' becomes 'anger' (I've seen this before).
'anger' with its final letter removed is 'ange'.
'ch'+'ange'='CHANGE'
'for' is the link.
(Other definitions for change that I've seen before include "Novelty" , "reform" , "It may be small" , "Innovation" , "Word for small coins in pocket" .)