Altering default options for dropdown menus

Our membership team has requested that I change the default creditee type for when a membership gets assigned from one customer to another. This conversation came up once before and according to our team, I did find a way to change the default designation. The dropdown lists the options in alphabetical order by description, but it always defaults to the second option when they want it defaulting to the first option. I can't for the life of me figure out how I did it, or even if I did manage to change it before. I can't find any documentation on it either.