25 C.F.R. § 215.20
Leases granted or approved under the regulations in this part may be assigned and the leased premises may be subleased or sublet, but only with the consent and authority of the Secretary of the Interior and subject to his approval as to the terms and conditions of such assignments, sublease, and subletting contracts and not otherwise, and provided also that the proposed assignees, sublessee, or sublettee shall be qualified to hold such lease under the regulations in this part and shall furnish such bond as may be required by the Secretary of the Interior, such bond to be with responsible surety to the satisfaction of the Secretary of the Interior and conditioned for the faithful performance of the covenants and conditions of the lease. Upon the filing with the Indian agent of such assignment, financial statement, and bond, the said agent shall at once give notice in writing to all restricted Indian owners of said land, advising them of said proposed assignment, and that if they have any bona fide objections to same, such objections must be filed in writing within 10 days from the date of said notice.
25 C.F.R. § 215.20