Whenever it appears to the satisfaction of the commission that the base named in any certificate of indemnity or scrip is invalid, or has been used in a previous State indemnity selection, or will not be accepted by the Land Department of the United States, the owner and holder thereof may surrender the certificate of indemnity or scrip to the commission. The certificate of indemnity or scrip shall thereupon be canceled, and the commission shall issue a new certificate of indemnity or scrip in lieu thereof containing an equal amount of acres of valid bases. If the base land described in the canceled certificate of indemnity or scrip has been used in making a State indemnity selection for the owner, the commission shall forward to the United States Land Office an amendatory of the State indemnity selection by substituting the base land described in the new certificate of indemnity or scrip for the base land in the certificate canceled by it.