I have roommate who is not on the lease and I want to get her out. I am 50% of the lease.
My other roommate on the lease is away in India. Do I need to have her permission too or can I just give the unwanted roommate 30 days notice.
She is not willing to have a civilized conversation of all the problems I have with her.
What can I do?
Please help.
Thanks.

If she is not on the lease, the she is just a "guest" unless you have some type of written agreement with her in place of her being on the lease.

Without anything in writing, I would just tell her to leave. Depending on how long she has "been a guest", I might even threaten to call the police and have her removed or charged with trespassing.

If you want to be nice, sure, give her a written 30 day notice, and mail it to her by certified mail so that she has to sign for it, and you can prove she got it if she takes you to court.

Has this roommate ever paid any rent? If so then she is a tenant and you must follow the law in your location for termination of her tenancy and filing a lawsuit for eviction if she does not leave.

At the top of the Real Estate Law forum is a sticky post with links to the laws for all of the states.