To assume a new last name, you should first obtain certified copies of your marriage certificate. Then work with each agency to change its record of your name. These may include:
All marriage license documents are signed with one's current legal name, never the intended new name.
There is no legal requirement for a name change after getting married; it is a right a couple may choose to exercise.
If you intend to change your name after marriage, check with each agency for its requirements to change your records. If an agency requires more than a certified copy of your marriage certificate, check with Yakima County District Court for details on a court-ordered name change.
Washington state law does not impose a time limit by which a name change must be accomplished after the wedding. However, if you are making the change more than one year after your wedding, check with each agency to determine if a certified copy of your marriage certificate will be sufficient to change your name with them.
Once a certificate is submitted to the State, you must complete the affidavit of correction form and submit to the State.