Not much going on in January of 1863, so this order issued on January 25th, seems to be it.
I’m copying it verbatum.
I. The President of the United States has directed:1st. That Major-General A. E. Burnside, at his own request, be relieved from the command of the Army of the Potomac.
2d. That Major-General E. V. Sumner, at his own request, be relieved from duty in the Army of the Potomac.
3d. That Major-General W. B. Franklin be relieved from duty in the Army of the Potomac.
4th. That Major-General J. Hooker be assigned to the command of the Army of the Potomac.
II. The officers relieved as above will report in person to the adjutant-general of the army.
It seems Burnside gave Lincoln an ultimatum that he remove several of his other generals or Burnside would resign. As a result, Lincoln removed Burnside and appointed General Hooker as commander of the Army of the Potomac.
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