California Code, Public Resources Code - PRC § 3908

If at any time the locator of any mining claim, or his or her assigns, apprehends that his or her original location notice was defective, erroneous, or that the requirements of the law had not been complied with before filing, or in case the original notice was made prior to April 28, 1939, and he or she is desirous of securing the benefit of this chapter, the locator, or his or her assigns, may file an amended notice, subject to this chapter, if the amended location notice does not interfere with the existing rights of others at the time of posting and filing the amended location notice. No amended location notice or the record thereof precludes the claimant from proving any title as he or she may have held under previous locations.