Take sth up ( phrasal verb ) : to discuss something or deal with something The school took the matter up with the police. UK I'd like to take you up on your sales figures for June. A leading law firm took up his case.

It depends on the context. "Take it up" can mean to deal with something in discussion. "No one is happy with the new plan. We'll take it up at the next meeting and see if we can improve it."