Try each of the following steps in order until the issue is resolved:

 
       
    • Ensure the user has rights to merge letters:
      1. In Administration, click Security.
       
      • Double-click the group of the user experiencing the issue.
       
      • Under Group Privileges, mark Configuration and click Options.
       
      • Mark the Letters checkbox and click OK.
       
      • Click Save and Close.
         
      • Update the letter:
        1. Go to Config, Letters, Constituent.
         
        • Open the Letter code.
         
        • Make a change to the title and change it back.
         
        • Click Save and Close.
         
        • Go back to the Constituent record.