Backdating an action is an available feature in Direct Actions. You will see the Backdate action checkbox in the bottom left of the action page.
The system will only allow backdating if it does not overlap with another movement action.
Note: Analysis, Addition, and Custom Actions are not considered movement actions, and therefore can be backdated to any time in the history of a lot. Movement actions can also be backdated to before those actions, but not before other movement actions.