You need to delete the dependent off your tax return. Even if you indicated that ''the other parent is claiming this dependent'', the child is most likely still there.
Click on MY INFO on the left side menu and scroll down to where the dependents are listed. Use the trash can icon or delete button to remove any dependent(s) that you are not claiming. If you need to remove the Dependent Care Credit, use this link. How do I delete Form 2441 in TurboTax Online?