GL Accounts can't be updated for the original Journal Entry, however, you can make a formal adjustment so the CR GL Account on the AR Item is now correct.
- Navigate to the Adjust tab of the Invoice Header record;
- Select Tentative Adjustment reason as 'Transfer: Different GL'.
- Specify the GL Account and the Tent. Adjustment date.
- Press Update.
This will cancel the original (incorrect AR Items) and create new AR Items with the correct CR GL Account.