You do not need a transfer or an assignment from the Administrative Judge to allow another judge in the courthouse to sign an order for you if the judge of the court where your case is pending is not available (assuming the clerks and the other judge cooperates).
Texas Government Code Sec. 79.094 says:
Sec. 74.094. HEARING CASES. (a) A district or statutory county court judge may hear and determine a matter pending in any district or statutory county court in the county regardless of whether the matter is preliminary or final or whether there is a judgment in the matter. The judge may sign a judgment or order in any of the courts regardless of whether the case is transferred. The judgment, order, or action is valid and binding as if the case were pending in the court of the judge who acts in the matter. The authority of this subsection applies to an active, former, or retired judge assigned to a court having jurisdiction as provided by Subchapter C.