I have two tenants in an office building who have not paid the rent. THey have made it clear that they have no intentions of paying the rent. I gave a three day notice to pay or quit on the 10th of the month. One tenant said 7 days later that he is going to take me up on leaving but not move out until the 31st of the month.Can I change the locks?

I forgot to mention that I am in California.

You can't change the locks until after you evict them. Good riddance! Commercial eviction made easy. | Legal > Property Law from AllBusiness.com

Sorry NO, changing the locks without a court ordered eviction is never legal. You can go after any property they may have in the offices or property but it is done though court