If I opt out of the additional child tax credit shouldn't it reflect immediately?

[cloud_cobra_numb]

Partners job had a clerical error and didn't put her selection for federal tax withholdings. So naturally we now owe that money. I am trying to not claim the additional child tax credit to help offset the Federal amount due. I select not to claim it and nothing happens. Am I doing something wrong? I feel like I either misunderstand how that works or it's something simple.

[DoninGA]

Why would you not want to use the child tax credit?  It reduces the amount of federal taxes owed.

The only way to opt out of the child tax credit is to remove the child as a dependent on your tax return.