Wash. Rev. Code § 78.08.080
If at any time the locator of any quartz or lode mining claim heretofore or hereafter located, or his or her assigns, shall learn that his or her original certificate was defective or that the requirements of the law had not been complied with before filing, or shall be desirous of changing his or her surface boundaries or of taking in any additional ground which is subject to location, or in any case the original certificate was made prior to the *passage of this law, and he or she shall be desirous of securing the benefits of RCW 78.08.050 through 78.08.115, such locator or his or her assigns may file an amended certificate of location, subject to the provisions of RCW 78.08.050 through 78.08.115, regarding the making of new locations.
RCW 78.08.080
*Reviser's note: "passage of this law": 1899 c 45 (H.B. 272) passed the house, February 27, 1899; passed the senate, March 7, 1899, and was approved by the governor March 8, 1899.