I need to put out a roommate who is not on my lease. Even though she pays her portion of the rent she does other things that have become annoying. For instance she eats my food, allows her dog to pee on the floors and walls and refuses to clean it up, and her attitude is horrible. She has changed the entire dynamic of the house in a negative way. We have not signed a sub lease or agreement of any kind. We only have a verbal agreement on a month to month basis.
My issue is that I went into the lease with one of the other roommates. The two girls have befriended each other so I know my lease mate will fight me on evicting this girl. So my main question is can I put this girl out with the required thirty day notice or do I need my lease mate's consent to proceed?
I have replacements ready to go in the event she moves out. We are all females. We live in Montgomery county, Pa.

If you and the original roommate are both on the lease, then you both have to agree on evicting. If the other roommate won't agree you are stuck until the end of your lease.

If you can agree, then give the 3rd roomie 30 day written notice, signed by both of the leaseholders, to vacate.