If you have Brian’s Song, there are some potentially useful lines for Lando.
From this exchange (found on IMDB, as I haven’t seen the movie for ages and can’t find the scene on YouTube):
Brian Piccolo: I said thank you.
Gale Sayers: I know.
Brian Piccolo: Well, usually when someone says thank you you’re supposed to say you’re welcome or How’s Your mother?
Gale Sayers: How’s your mother? ?
Brian Piccolo: She’s doin’ fine, thanks for asking.
You could pull the line, “How’s your mother?” when Han and the Gang arrive at Cloud City.
You could have Leia confess her love to Lando instead of Han, and Lando could respond, “I know.”