Until your return moves into accepted status, you won't be able to amend. In fact, you won't be able to do anything with your return.

But here's what you can do in the meantime:

1. Keep checking your e-file status or watch your email inbox for a status update.
2. Once your return is accepted , you can amend. (If your return gets rejected, make the necessary changes before re-sending or filing.)
3. If you're amending to claim more money, the IRS says to wait until you've received your original refund before filing an amendment.
4. Once you've received your original refund, feel free to cash or spend it while your amendment gets processed (this can take 12–16 weeks).
5. To amend, see How to amend (change or correct) a return you already filed.
6. Three weeks after you mailed your amendment, you can start tracking its progress at the IRS Where's My Amended Return? site.

Related Information: 

• What does it mean to "amend" a return?
• Can I cancel a pending return?
• How do I cancel or undo an amended return in TurboTax Online?
• How do I cancel or undo an amended return in the TurboTax CD/Download software? 

[Edited 3-11-2020|9:42 am PST]