Wash. Rev. Code § 8.12.340
The court before which any such proceedings may be pending shall have authority at any time before final judgment to modify, alter, change, annul or confirm any assessment returned as aforesaid, or cause any such assessment to be recast by the same commissioners, whenever it shall be necessary for the obtainment of justice, or may appoint other commissioners in the place of all or any of the commissioners first appointed for the purpose of making such assessment or modifying, altering, changing or recasting the same, and may take all such proceedings and make all such orders as may be necessary to make a true and just assessment of the cost of such improvement according to the principles of this chapter, and may from time to time, as may be necessary, continue the application for that purpose as to the whole or any part of the premises.
RCW 8.12.340