Claimed dependent

If your significant other has filed their return first, then your return maybe rejected.  Two people cannot claim the same dependent.  If your return gets rejected, then you can remove your dependent & then re-e-file.

If your return is accepted, you would have to amend your return to make any changes.  Amended returns must be mailed. The amendment form (1040x for Federal) is not available in TurboTax until mid to late February.  You would have to wait until the form is available to amend your return.

To amend a return, if you used TurboTax Online, simply log in to your account and select “Amend a return that was filed and accepted.” If you used the CD/download product, sign back into your return and select “Amend a filed return.”

Three weeks after mailing your amended return, you can start tracking it at the IRS Where's My Amended Return? tracking tool.  Please allow at least 16 weeks for the IRS to process your amended return.

To add to bluedeb's excellent advice:

While waiting for the 1040X to become available, DO NOT go in and start changing anything on your return in the system, or you will make a mess for yourself.  Sit tight and wait until you see what the IRS does with the return you just e-filed.

Please see the instructions contained in these TurboTax Help articles to amend your return: 

• How to amend (change or correct) a return you already filed
• How do I amend my 2019 TurboTax Online return?

As bluedeb stated, the 1040X form (amended) return won't be available until probably late-February.  For current information on forms availability please click on the applicable link below:

• Federal forms
• State forms