OK they have to mail their return. You need to amend yours. They don't have to wait for your Amended return to process.
How to Amend this year
When your tax return has been fully processed you can amend and change the way you answered the question in My Info when it asked you if you can be claimed as someone else's dependent.
See this TurboTax support FAQ for amending a tax return - https://ttlc.intuit.com/turbotax-support/en-us/help-article/tax-return/amend-change-correct-return-a...
Meanwhile, your parents do not have to wait for you to do that. It will not help them. They will not be able to e-file this year. You put your SSN into the system for the year. They will have to file by mail. They need to print, sign and date their return in ink, and mail it to the IRS and state. They will have a longer wait for their return to be processed.
When you mail a tax return, you need to attach any documents showing tax withheld, such as your W-2’s or any 1099’s. Use a mailing service that will track it, such as UPS or certified mail so you will know the IRS/state received the return.
Federal and state returns must be in separate envelopes and they are mailed to different addresses. Read the mailing instructions that print with your tax return carefully so you mail them to the right addresses.