Idiom
take someone up on something
Theme: ADVANTAGE - TAKE
to take advantage of someone's offer of something. (Informal.)I'd like to take you up on your offer to help.We took up the Browns on their invitation to come to dinner.
Idiom
take someone up on somethingtake (someone) up on (something)
to accept (an offer or invitation) from someone.I think I'll take him up on his offer of a free ticket.