Answer:
If the owner died their estate must be probated in order for title to vest in the heirs or for the estate fiduciary to have the legal power to sell. If they left a will (testate), the will must be allowed and an executor appointed. If they died intestate an administrator must be appointed. The administrator of the estate can obtain a license to sell the property from the court. The executor can obtain a license to sell if there is no authority to sell in the will. However, the debts of the decedent must be paid before any property is distributed to the heirs.
No one has any authority over the property until the estate is probated so until then, no one can give a valid deed.