1. For changing the surname of your son from his biological father to the surname of your present husband, he has to take you son in adoption by executing and registering an adoption deed legally,
2. For registering the adoption deed, you shall have to take consent from the biological father of your son,
3.You shall have to try to contact him at his last know address,
4. If you fail to locate him, you shall have to file an application for permitting your present husband to take your son in adoption without the written consent of his biological father since he is missing,
5. If the court passes order granting your prayer then with the help of the Court order, your present husband can execute and register an adoption deed without the consent of your earlier husband,
6. Please also note that such order from the Court is very difficult to get.