If your customer signs the lease agreement before the warranty agreement, the warranty agreement must be signed by deed. Very often, the tenant`s parents are guarantors, provided that the parents are in a healthy financial situation and agree to take on this role. It is very common for young adults not to have the credit score and financial history that landlords need for a lease, and a parent or other parent often comes in to sign a guarantee clause, with the young adult being the primary tenant. As the young adult receives a financial history of one-time payments, future leases are usually not a problem. There is a legal obligation that a warranty agreement be in writing. The agreement defines the legal obligations of the guarantor. Less often, a guarantor may be an unrelated friend, a co-worker, or even a company.