can you serve the daugther of the defendant if she will not let you serve her father who you are tryiny to sue? She is over 18 years old

Most states allow you to serve the defendant by serving someone responsible at his/her/its home or place of business.  For example, you can serve a defendant in N.Y. by serving anyone of suitable age and discretion at the defendant's actual place of residence, and then mailing a copy to the defendant at that address.  However, while I am confident that  Washington has a similar law, I am not 100% sure.  Also, the service rules in small claims court are sometimes different than those for the other courts.  The clerk of the small claims court should be able to help you.