After the household registration book is lost, the head of household should report to the police station in time and submit a written application (the application must be signed by all adult members of the family). If the head of the household is unable to apply to the police station for other reasons, he shall issue a written entrustment application, and the entrusted person shall be an adult of the household; If you can really entrust other people in this household, you should apply for a replacement after the police visit and investigate.