I will close soon a new purchased house in California . An existing tenant has been there for one year, without any lease agreement, never paid rent; The tenant informed me that she will move out upon finding new place, how can I get her out as soon as possible or have her signed up a lease during her staying at my house? Can I change new locks but provide copy of keys to her? Or request a key to her house so that I can perform repairs or showing to potential clients? Thanks!:

You should check into the local laws in your community regarding eviction, the do differ from one county to another and from state to state.

You now hold all the cards. You can try to work out a new least agreement on your terms, how much rent, length of lease, and how much security deposit you require. If you want to continue to rent to this person, present them with the new terms. They can accept, or deny them. If they accept, stick your hand out and demand payment. If they can't pay, then start the eviction process. If they refuse the new terms, give them the required notice to vacate and follow the laws for your county if they refuse to leave.

Good Luck!

Was the tenancy part of the sales contract? If not, she has no right to be there. You can have her removed but it will take time. Personally, I would never have agreed to having a previous tenant in there at the time of sale. Check you sales contract and ask your lawyer,, that is why you have him!