First, login to your Manager Account. 

Locate the "declined" event and click on the "event name".

Click on the "edit event" button.

Click on the "Open event" icon.

To re-assign to the same BA

If you need to re-assign it to the same BA , click on the "refresh" button. 

Click on "confirm" to confirm that you are re-assigning to the same BA.

And then click "Save".

Voila! That's it!