You can reschedule your interview right in the app:
If you find that you are unable to attend an interview that you accepted, please cancel the interview on your app and accept a different interview that fits your schedule. Please note, if you are unable to find a new interview at first glance, they are posted every week. Also, please keep in mind that excessive cancellations of interviews can negatively impact the interview decision.
To reschedule your interview, you must first cancel the interview that you no longer want to attend. To cancel an interview, you click on the button associated with the session you'd like to cancel (In this example, Tuesday, August 28th).
You will be brought to the interview post, then you'll have to scroll to the bottom of the post and select "cancel job."
After you've canceled the interview, you can go back into the app and select the opportunity that works best for you.