https://davidallengreen.com/2021/01/can-a-presidential-pardon-be-revoked/ https://davidallengreen.com/2021/01/can-a-presidential-pardo... discusses — in 1869 on

https://davidallengreen.com/2021/01/can-a-presidential-pardon-be-revoked/ https://davidallengreen.com/2021/01/can-a-presidential-pardo... discusses — in 1869 one got rescinded because the original was never delivered (but according to the post that isn't binding).