I need to take off one of my child off off my taxs how can i do that?

Have you already filed your tax return? If so there's nothing you can do now except to wait and see if the return is accepted or rejected. If it's rejected you can sing back into your TurboTax account, modify your return, and resubmit it. However if it's accepted you'll have to file an amended tax return. 

See the instructions for filing an amended tax return here: https://turbotax.intuit.com/tax-tips/amend-return/how-to-file-an-amended-return-with-the-irs/L6kO691J8 

Before filing an amended return, make sure the IRS has already processed the tax return you need to amend. That way, you can ensure the IRS won't get your original return and amended return mixed up. If you've already received your tax refund, then you know the IRS has already processed your return.