How do you change the name of an existing liability account in the general ledger?

Let me help you set up your retirement plan in QuickBooks Desktop, LM1951.

When setting up a 401k plan, we choose the account in the Liability account field that tracks the deduction or contribution to be paid. The option to change the liability account that is already set up in QuickBooks is unavailable. However, we can Set up the deduction item to post the payroll deductions from the employees. Let me show you how:

1. Go to Lists, then Payroll Item List.
2. Click the Payroll Item ▼ dropdown, then New.
3. Choose Custom Setup, then Next.
4. Select Deduction, then Next.
5. Enter the name of the deduction, and Next.
6. If applicable, select the name of the plan administrator (or add it), and the account number. Then select Next.
7. Select the applicable Tax tracking type. Select None if the deduction is after-tax.
8. Select Next three times. For None tax tracking type, select net pay in the Gross vs. net window, then Next.
9. Leave the Default rate and limit fields blank unless these apply to all of your employees. You’ll add the rate and limit when the item is added to the employee profile.
10. Press Finish.

Once done, add the item to the employee profile. Let me guide you on how: 

1. Go to Employees, then Employee Center.
2. Select your employee.
3. Click ✎, then choose Payroll Info.
4. From Additions, Deductions, and Company Contributions, add the deduction item.
5. Enter the amount per period and a limit if applicable.
6. Press OK.

You can check out this article for more details: Set up, change, or delete employee-paid payroll deductions. Once done, set up a retirement plan deduction or a company contribution in QuickBooks Desktop Payroll to track and tax it appropriately. 

In case you need to change the expense or liability account associated with your payroll item, you can refer to the following write-up: Change an expense or liability account associated with a payroll item.

I want to be your main point of contact, so please let me know if you have any other concerns or questions about the 401k set up. Please know I'm ready to assist further. Have a good one.