My daughter accidently claimed herself and my returns are being rejected. Where is the "Amend My 2020 Returns" option within Intuit Turbo Tax? Her returns R accepted.

You must mail your tax returns.  Even if she amends, it won't clear the e-file block.

The amending tool is usually available toward the end of February or early March.  Many forms are delayed this year because the IRS is backlogged implementing changes.  But your daughter should not amend her return until her tax return is completely processed and whatever refund she claimed is paid.  If she gets a large refund (such as, due to the recovery rebate) she will have to repay it, but there will be no penalties or interest as long as she files the amended return by April 15. 

Since your return was rejected, you can correct the dependent situation and re-file now. No amendment is necessary in your case. @Opus17 is correct if you still want to claim your daughter. She would have to amend.

But, if you want to leave things as they are and proceed with your own filing without it getting rejected, go back in your return and follow the prompts to fix the return. Otherwise, follow these steps:

• From the left menu, select My Info.
• Scroll down to her name and click the trash can icon to delete her information from your return.
• Run through the reviews again to make sure you are ready to file.
• File your return.

For more information about dependents, see: Who can I claim as my dependent?