Do what thirschfeld says. Your cookies will be fine.

Definitely NOT the dumbest question I've ever heard. . .or asked! I once made sugar cookies and forgot the sugar. I've doubled the recipe for pie crust, except for the flour. For 40 years, I've worked with chocolate but I still manage to make it seize up now and then. I've thrown meat into bags to marinate, then forgotten about it for days. Apparently, such kitchen skills are hereditary: I must've passed those genese down to my kids because last week, one son called to tell me that he made chocolate chip cookies with powdered sugar instead of flour. Feel better now?

does it contain baking powder? If so I might go without the soda. Otherwise I would mix the baking soda with a tablespoon of flour and then incorporate. If you need to add some liquid then do so, like a teaspoon or so.