Wash. Rev. Code § 36.69.250
Whether the improvement is initiated by petition or resolution, the board of park and recreation commissioners shall conduct a public hearing at the time and place designated in the notice to property owners. At this hearing the board shall hear objections from any person affected by the formation of the local district and may make such changes in the boundaries of the district or such modifications in the plans for the proposed improvement as shall be deemed necessary: PROVIDED, That the board may not change the boundaries of the district to include or exclude property not previously included or excluded without first passing a new resolution of intention and giving a new notice to property owners in the manner and form and within the time herein provided for the original notice.
RCW 36.69.250