To change the narrative you will need to follow these steps
From the Toolbar
Click on Nominal Ledger
Click on Nominal Accounts
Locate the Account
Click on Transactions
Click on the Narrative
Right Click and click on Modify
The user will then be able to change the Narrative.
Click on Apply
This is a restricted process so if the user does not have access to the Modify option then this will be due to user permissions.