How to delete future dated assignment changes?

Summary:

We had submitted a promotion change with a future date for an internal hire. However, we need to change the start date. We need to re-draft his offer letter.

Content (please ensure you mask any confidential information):

The promotion was already submitted and approved. How do I delete this? How should we handle internal hires and redrafting offer letters?

Version (include the version you are using, if applicable):

23D

Code Snippet (add any code snippets that support your topic, if applicable):