You can get the Form W-4 online, and give it to your employer anytime. Turbo Tax doesn't anything with your W4, so you can obviously just fill in the form from irs.gov.
https://www.irs.gov/pub/irs-pdf/fw4.pdf
If you would like to use our interview to complete the form anew, try this-
- go to Amend your return from the Tax Timeline
- when you are asked if you would like to amend, say No or ignore it.
- go directly to Federal Taxes- Other Tax Situations- Other Tax Forms- Form W-4 and Estimated Taxes Start or Update here