Both the current owner and the new owner must post agreeing to the statement.
Example:
Person A
I'm co-owning Joe Laya with Person B. We both have RP rights but only I have mating and breeding rights.
Person B
Person A
I'm co-owning Joe Laya with Person B. We both have RP rights but only I have mating and breeding rights.
I agree to the above statement.
