German law is characterized by freedom of contract. Within the framework of the law, there are no limits to the contractual arrangements you can make. On the one hand, this allows a great variety of agreements, on the other hand, it requires special formulations to avoid later conflicts about the intended content. I will be pleased to advise you both on the safeguarding before signing the contract and with the examination of your concluded contract as well as, if necessary, on the reversal of your contract.