Welcome to the Community, @Dandanezu. I'll help you update a credit card account number in QuickBooks Desktop.

My colleague above provided the steps to update the credit card number. Don't worry if you miss it. I will share the same steps.

You can disconnect and change the linked credit card account number (you don't have to disconnect all accounts).

Note that you won't be able to terminate an account if it still has transactions to evaluate. Before doing so, categorize them.

Here's how:

1. Go to Lists, then choose Chart of Accounts.
2. Find the connected credit card account, then right-click on it.
3. Select Edit account.
4. In the Edit Account window, click the Bank Feed Settings tab.
5. Tick Deactivate All Online Services.
6. Hit Save & Close.

Then, using the correct credit card number, re-establish the account:

1. Go to Banking.
2. Select Bank Feeds.
3. Choose Set Up Bank Feeds for an Account.
4. Follow the on-screen prompts to connect the credit card account again.

Check this link to learn more about adding an account in QuickBooks Desktop: Learn about the chart of accounts in QuickBooks Desktop.

Let me know if you have additional questions about the Chart of Accounts in QuickBooks Desktop. I'm always around to help.