PARTNERSHIP CONSENT REQUIREMENT FOR SELLING A JOINT HOUSE

FREE ADVICE-
My business partner & I've shared ownership of a rental house since 9/08. Each has a 50% interest (tenants in common). My partner now wants to sell her share. I'd like to know if the partner needs my consent to sell her share to someone else. If I were going to buy her out, without hiring a lawyer, what kind of paperwork would we need? Would a quit claim deed sign by the partner be sufficient? Is there any cost for transferring property ownership? Also, while waiting to sell her share, the partner plans to let her brother use some parts of our house to store his things. Is there any recourse I can take to prevent the partner's relative from using the house as his storage? Thanks for your assistance.