The requirements of Subsection (a) are demonstrated to the tribunal being asked to assume continuing, exclusive jurisdiction. No action to transfer, surrender, or otherwise participate is required or anticipated by the original order- issuing tribunal. The Act does not grant discretion to refuse to yield jurisdiction to the issuing tribunal; nor does it extend discretion to refuse to accept jurisdiction to the assuming tribunal when the statutory requisites are met. However, there is a distinction between the processes involved under Subsection (a)(1) and (a)(2). Once the requirements of (a)(1) or Section 613 have been met for assumption of jurisdiction, the assuming jurisdiction acts on the modification and then notifies the tribunal whose order has been replaced by the order of the assuming tribunal, see Section 614, infra. In contrast, for a tribunal of another State to assume modification jurisdiction under Subsection (a)(2) it is necessary that the individual parties first agree in a record to submit modification of child support to that tribunal and file their agreement with the issuing tribunal. Thereafter they may then proceed to petition the assuming tribunal to take jurisdiction.

Modification of child support under Subsections (a)(1) and (a)(2) is distinct from custody modification under the federal Parental Kidnapping Prevention Act, 42 U.S.C. Section 1738A, which provides that the court of continuing, exclusive jurisdiction may "decline jurisdiction." Similar provisions are found in the UCCJA, Section 14. In those statutes the methodology for the declination of jurisdiction is not spelled out, but rather is left to the discretion of possibly competing courts for case-by-case determination. The privilege of declining jurisdiction, thereby creating the potential for a vacuum, is not authorized under UIFSA, see Rosen v. Lantos, 938 P.2d 729, 734 (N.M. App. 1997). Once a controlling initial child-support order is established under UIFSA, at all times thereafter there is an existing order in effect to be enforced. Even if the issuing tribunal no longer has continuing, exclusive jurisdiction, its