Tries subtleness for a change in this type of correspondence (8,7)
I believe the answer is:
'this type of correspondence' is the definition.
Although both the answer and 'type' are nouns, they are not in the same form of the noun.
'tries subtleness for a change' is the wordplay.
'for a change' is an anagram indicator.
'triessubtleness' anagrammed gives 'BUSINESS LETTERS'.
'in' acts as a link.
Can you help me to learn more?