(1) A proceeding for the modification of an order of child support shall commence with the filing of a petition and worksheets. The petition shall be in the form prescribed by the administrator for the courts. There shall be a fee of twenty dollars for the filing of a petition for modification of dissolution.
(2)(a) The petitioner shall serve upon the other party the summons, a copy of the petition, and the worksheets in the form prescribed by the administrator for the courts. If the modification proceeding is the first action filed in this state, service shall be made by personal service. If the decree to be modified was entered in this state, service shall be by personal service or by any form of mail requiring a return receipt. Proof of service shall be filed with the court.
(b) If the support obligation has been assigned to the state pursuant to RCW
74.20.330 or the state has a subrogated interest under RCW
74.20A.030, the summons, petition, and worksheets shall also be served on the attorney general; except that notice shall be given to the office of the prosecuting attorney for the county in which the action is filed in lieu of the office of the attorney general in those counties and in the types of cases as designated by the office of the attorney general by letter sent to the presiding superior court judge of that county.
(3) As provided for under RCW
26.09.170, the department of social and health services may file an action to modify or adjust an order of child support if:
(a) Public assistance money is being paid to or for the benefit of the child;
(b) A party to the order in a nonassistance case has requested a review; or
(c) Another state or jurisdiction has requested a modification of the order.
(4) A responding party's answer and worksheets shall be served and the answer filed within twenty days after service of the petition or sixty days if served out of state. A responding party's failure to file an answer within the time required shall result in entry of a default judgment for the petitioner.
(5) At any time after responsive pleadings are filed, any party may schedule the matter for hearing.
(6) Unless all parties stipulate to arbitration or the presiding judge authorizes oral testimony pursuant to subsection (7) of this section, a petition for modification of an order of child support shall be heard by the court on affidavits, the petition, answer, and worksheets only.
(7) A party seeking authority to present oral testimony on the petition to modify a support order shall file an appropriate motion not later than ten days after the time of notice of hearing. Affidavits and exhibits setting forth the reasons oral testimony is necessary to a just adjudication of the issues shall accompany the petition. The affidavits and exhibits must demonstrate the extraordinary features of the case. Factors which may be considered include, but are not limited to: (a) Substantial questions of credibility on a major issue; (b) insufficient or inconsistent discovery materials not correctable by further discovery; or (c) particularly complex circumstances requiring expert testimony.
(8) If testimony other than affidavit is required in any proceeding under this section, a court of this state shall permit a party or witness to be deposed or to testify under penalty of perjury by telephone, audiovisual means, or other electronic means, unless good cause is shown.