That allows converters to combine apartments and sell vacant units at a much higher price.

Ms. Lenz said combining apartments "never occurred to people five years ago."

Aqua is the first downtown building to combine condos, apartments and a hotel.

The original plan called for a single mixed-use building combining office space, hotel rooms and apartments that would occupy the entire site.

It combined residential townhouses, apartments and high-rises with commercial areas.

Price Tower was one of the first tall buildings to combine offices, stores and apartments.

People are better off, she suggested, if they combine apartments in buildings that have already had a lot of experience with the process.

Mr. Davis said tenants will also have the option of combining apartments.

Ms. Kruglova thought his plan to combine apartments someday was absurd.

As renters and studio owners move out, buyers are breaking through walls to combine apartments.