A contract with a condition precedent. For example a contract subject to:
an existing lease being transferred to the purchaser of a business with the consent of the lessor.
a lease for a specified term( with an option for a further specified term if applicable) at a specified rent and conditions sufficiently identifiable and acceptable to the purchaser being granted to the purchaser of the business.
If the purchaser is not successful in having the existing lease assigned, or a new lease created the contract will be void and the purchaser entitled to the deposit in full.