The head of the household is not necessarily the owner, and the demolition agreement needs to be signed by the owner. Of course, if the owner is the head of the household, then it is also signed by the head of the household. If it is neither the head of the household nor the owner, it depends on whether the signatory has a power of attorney. If there is a power of attorney, there is no dispute. If there is no power of attorney, the key depends on whether the signatory belongs to the agency by estoppel.