i would like to add my last name to my babies name, who's father is absent
If the father will not file a Consent to the change of name petition, you can file it as a contested case and have the Court issue a Show Cause Order to the father to file an objection to your request within a certain period of time. You will need to provide the Court with a good address where the father can be served.
If he does not object timely, the Court can hear your reasoning and make a determination as to whether or not the change of name is in the best interest of the child. As with all name change petitions, yours will have to be published once in the newspaper as well.