Section 168.9 - Assignment, modification and cancellation of permits(a) Grazing permits to Hopi tribal members shall not be reassigned, subpermitted or transferred without the approval of the permit issuer(s).(b) The Area Director may revoke or withdraw all or any part of any grazing permit in Hopi Partitioned Lands by cancellation or modification on 30 days written notice of a violation of the permit or special conditions affecting the land or the safety of the livestock thereon, as may result from flood, disaster, drought, contagious diseases, etc. Except in the case of extreme necessity, cancellation or modification shall be effected on the next annual anniversay date of the grazing permit following the date of notice. Revocation or withdrawal of all or any of the grazing permit by cancellation or modification as provided herein is effective on the date the notice of cancellation or modification is received and shall be appealable under 25 CFR part 2.