Legal Question in Real Estate Law in California

Yes, otherwise the siblings who do agree will only be able to sell their interest, which will be practically difficult. Your other option is to look at a partition by sale action.

I agree with Mr Roach. While any co owner can force a sale through partition, that is time consuming and expensive. Partition actions can be used as a threat to those reluctant to sell because of that cost. It is far better to have an agreement to move forward.

the above is correct