Ariz. Rev. Stat. § 12-403
All actions and proceedings, civil and criminal, pending at the time of the organization of a new county or the changing of county boundaries, if such action or proceeding should have been instituted in the new or changed county had it been organized before the institution thereof, shall be transferred to the new or changed county, and filed, docketed and proceeded with in like courts, or before like officers of the new county. The original papers shall be sent and transferred to the new or changed county, together with authenticated transcripts of the proceedings had therein up to the time of the transfer, and the courts and officers of the new or changed county shall have the same jurisdiction in, and power over, the actions and proceedings as they would have, had they been originally begun in or before them. Any failure or defect in a transcript or the authentication thereof, or transfer, may be cured at any time.
A.R.S. § 12-403