Adobe Campaign

Hello everyone, would you be able to help me to define an expression in an "update data" activity ?

I want to import a file containing values = "unknown". But for every values = unknown, I want to import an empty value in Adobe Campaign. So I need to create an expression that convert a value = unknown into a empty string in adobe.

I know there is the expression "NoNull <Value>" that returns an empty string if the argument is NULL, but I would like to do the same if the value = unknown.

Thank you for your help 🙂