AI Code is No Longer Visible

I am trying to add an AI code to a constituent record, but it is no longer showing in my list of AI codes when I click the pop up. How do I get that back?

The code has most likely been marked as inactive. If you go to AI Codes Maintenance, locate the code in the list. If it has a line through it, it is inactive. Double-click the code, and select the "Active?" box. Click OK. The code will now be active, and able to be selected from the constituent record.