Usage patterns
〈事〉で残念だto be disappointed because of ~
I'm disappointed that we lost the match.
残念な〈事〉a disappointing ~ (news, result, etc.)
It turned out to be a disappointing result.
とても残念だto be very disappointed or regretful
I'm very disappointed that the trip was cancelled.
〈人〉は残念そうだsomeone looks disappointed
He had a disappointed look on his face.