If you find yourself in a bind with an incomplete renovation abandoned by your contractor, the simplest way to find out what you need to do is to attend one of the department of buildings (DOB) weekly “Homeowners Nights” meetings, which are held Tuesday evenings in each borough. You don’t need an appointment. Just explain your predicament to the department representatives, show them what paperwork you have pulled together, and ask them what you should do.

For minor — so-called Alt 2 or Alt 3 — alterations, you may need to do no more than just get a sign-off from the original contractor. If you can’t track them down, you can hire a professional; perhaps even the building’s own architect or engineer to check the work and prepare a notice of completion for the DOB. It will then issue a letter of completion.

Getting OKs for more extensive Alt 1 renovations may cost you more money and time, and will require more legwork at the DOB, along with an official inspection.