I can't enter a new W-4 for an employee who wants to change withholding

Glad to have you here, Lisa2112.

I can walk you through how to correct your employee's W4 information in QuickBooks Online (QBO).

Here's how:

1. Go to the Payroll menu and select Employees.
2. Click the name of the employee, then click the Pencil icon beside Pay.
3. Go to Step2 or the part where the employee's withholding or W4 are set up, then click the Pencil icon underneath it.
4. Scroll down to Federal withholding and click the link for Need a blank W-4 form.
   
5. Enter the correct information.
6. Click Save.

Check out this article about managing employee details for further guidance: Edit or Change Employee Info in Payroll.

Here's an article you can read to learn more: What’s changing with the Federal W-4?

To know the items that will post in Box:2c here's a great article that you can read: W2 form boxes explained.

If you're still unable to correct it, I suggest contacting our QuickBooks Care Team. This needs further investigation so our team can take a closer look and come up with a solution to change the W4 information.

Here's how:

1. Go to the Help menu at the upper right.
2. Select Contact Us.
3. Enter your concern.
4. Click Let’s talk.
5. Choose Get a callback. 
6. Type in your contact info.
7. Select Confirm my call.

You can check out this article for our most updated contact information: Support hours and types.

I'd also like to give you these articles for additional information and reference:

• Payroll Tax Liability Report
• Run Payroll Reports

Anything else you need help with managing W4's can be answered in the Community. Feel free to visit us again and I'll be around to assist. Stay safe and have a good one.