Mark a Letter as Inactive
If a letter is no longer current and your organization no longer uses it for a marketing effort process, you can mark it as inactive from the Letters and Documents page. On the Letters tab, select the down arrows next to the letter to mark as inactive and select Mark inactive. When a confirmation message appears to ask whether to mark the letter as inactive, select Yes. You return to the Letters and Documents page.
To view inactive letters on the Letters tab, select Filters. select Include inactive letters, and select Apply.