first come first serve parter problem in pa

[Mike Parks]

Rather than get charged by my attorney I figured I would see what kind of response I get here first from all my knowledgeable peers.

I own a property 50/50 with someone and my name is on the LLC and on the mortgage. I essentially "gave" this certain someone the property. What I mean by that is he would be 100% responsible for everything IE: mortgage, insurance, maintenance, etc. Net rental income would be his. Here's where things get ugly.....

Property was refinanced back in July 2014 and has been sitting vacant since, he has been covering the mortgage, so great. I have found a qualified tenant who agrees to pay what MY asking rental price is. Now the "someone" seems to think that this place is worth more (which it may be but not much) but he hasnt been able to find a tenant. Clearly its a price issue. My question is this....

If I meet the potential tenant, get the lease signed, accept security deposit, and hand over keys, is there anything that this "someone" can do since I am 50/50 owner and am just as much financially responsible as he is and even more importantly can he do anything to the tenant once the lease is singed?