Many applications say that if a potential tenant declines the rental after applying, they will lose their application deposit. Typically, there’s no grace period for backing out of the application once it is signed. If the landlord says a tenant can cancel the application and get the deposit back, it must be in writing in the application agreement.
Even without a signed application agreement, the landlord might still keep part or all of the deposit.
If a tenant has signed a lease and paid a security deposit or prepaid rent but does not move in, they usually can receive a full refund only if (1) the tenant finds a replacement tenant approved by the landlord and (2) the substitute tenant moves in by the lease start date.
If the landlord finds a replacement tenant, they can take money from the security deposit or rent prepayment. This can cover any agreed lease cancellation fee or actual costs, including the time spent finding a new tenant.