Swap brooklyn apartment for another in NYC

An apartment in Greenpoint to swap for anywhere in else in NYC with a lift (or on 2nd floor) near a pool, park or gym? Posting this on behalf of an injured friend who cannot climb stairs up to her 4th floor apartment in Greenpoint. She is in rehabilitation and just wants to get her strength back with easy walking. Time period negotiable, her place is two floors with two bedrooms, balcony and private roof deck, thank you for any help/ideas.