party to the transaction vs party to the action

party to the transaction and party to the action both are nouns.

Word	Noun	Adjective	Verb	Adverb
party to the transaction	Yes	No	No	No
party to the action	Yes	No	No	No

As nouns, party to the transaction and party to the action are synonyms defined as:

party to the transaction and party to the action: a party of people taking a role in legal proceedings

party to the transaction (noun)	party to the action (noun)
a party of people taking a role in legal proceedings	a party of people taking a role in legal proceedings