Section 530
Only The Parties To Contract Can Demand Its Performance
(1)
Only the person who is a party to a contract can demand the
performance of the contract by the other party.
Provided that if a contract is concluded for the benefit of any
person, such a person can demand the performance of that contract
even if he or she is not a party to such a contract.
(2) If two or more persons jointly enter into contract to do
or not to do any act, all such a persons can jointly demand the
performance of that contract, except as otherwise provided for in
the contract.