Although I don't practice in your state, the standard used is "due diligence" in the attempt to serve the other party. Since your facts are not specific, I only gave you general principles of law involved.
If you have filed a lawsuit and need to serve a Complaint, review Arizona Rules of Civil Procedure 4 and 4.1 (and 4.2 if the parties are out of state). Normally, you have 120 days after you file a Complaint to serve it. This time can be extended by motion.
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