In essence they become a co owner of the note.

You are more or less just a co-signer on your sister's lease, so the apartment is not your primary residence.

Just sign up to be a co-host.

It's kind of a neat environment, like a co-op apartment complex, depending on the other owners and their goals. 

I started years and years ago by having 2 friends and a co-worker live in a big house I bought and paying me more rent than my payment and 3/4ths of the utilities.  

I’m looking for a company who can clean up asbestos in my 2/2 condo in Culver City, CA - received a quote that it would be in the area of $20k and I’m hoping to find a co that will either provide financing or place a lien that I can pay off when I sell the property which will go on the market immediately after the cleanup is completed.

I am looking into the possibility of buying a Co-op in New York City in the near future.

If HELOC isn't approved due to credit/DTI -- Pay for/find a co-signer willing. 2.

You don’t need a CO for a cash sale but do need it to move someone in.  

@Franka Hauck - You most likely couldn't put the rental portion into an LLC while keeping the primary residence portion in your name unless the property is split on the deed, or it is setup as a co-op or condo type situation.Keep in mind, the purpose of an LLC is asset protection.