> **If you have full editing privileges, and:**
> 
> - If you are still in the grace period, you can simply edit it back to its original form and the revision will completely disappear as if it
> never happened.
> 
> - If you are past the grace period, you can roll the edit back by clicking the "rollback" link on that revision in the post's revision
> history.
> 
> **If you don't have full editing privileges** you have to manually revert the post to its original form as a new suggested edit, which
> will have to go through the review process again to be approved.

Above is a copied excerpt from [this answer](https://meta.stackexchange.com/a/158366/238020)