Tables :: Hide Inactive Status From Dropdown Box In Other Table

I have some tables with data where in one column the user will choose a status between 30-40 different options. They are choosing this option to show a reason why a trade was pended and not approved immediately. These reasons seem to change frequently and sometimes we no longer want to use an old reason.

I do reporting back several years, so I cannot just 'remove' a reason or it will be removed from the table and I will have blank reasons. When selecting the specific reason, the table takes the dropdown from another table that simply lists every possible reason. I want to know how I can make it so that the reason that is no longer in use remains on that connected table, but when the person entering data clicks the dropdown button, the removed or inactive reason no longer shows up as an option.

Previously I had seen people add a column to the connected table of reasons and use a "yes/no" check box to show if the reason is now Inactive. When you checked YES on inactive, the reason would disappear from the dropdown list. My issue is that I do not know what language or formula to use (or where to use it) so that when I click Inactive = Yes, the reason disappears from the dropdown menu.