When was the 1st Kansas Colored Infantry officially designated the 79th U.S. Colored Troops?

The first reference I find in the ORs is a report dated April 20, 1864 from Lt. Edward Ross, 2nd Kansas Cavalry, addressed to “Col. J. M. Williams, Seventy-ninth U. S. Colored Infantry”. However, Williams’ own report of April 24th refers to the regiment as the “First Kansas Colored Volunteers” and he signs the report “Col. First Kansas Colored Vols.”. In Oct 1864, Brig. Gen. Thayer at Ft Smith refers to the regiment at the 1st Kansas Colored.

On Oct. 20, 1864, C. W. Foster, AAG of Volunteers, submits a “report of the operations of this Bureau during the past year” to “Adjt. Gen's. Office, Bureau For Colored Troops” stating:

By direction of the Secretary of War, the designation of the regiments composing the corps d'Afrique, in the Department of the Gulf, has been changed to U. S. Colored Troops, and the enlisted men of five of said regiments, viz, Seventy-ninth, Eighty-third, Eighty-eighth, Eighty-ninth, and Ninetieth, distributed among the remaining twenty-three regiments of that corps. The supernumerary officers have been mustered out of service, subject, however, to examination, with a view to their reappointment in other colored regiments, under regulations established by Maj.-Gen. Canby, subject to the approval of the Secretary of War.

Anyone know the official date of the change?

Ken