How to change Kentico 11 culture through an API from external application?

Hi, we run an external MVC application connected through the API with Kentico 11. Both of them share the same Authentication cookie. We need to be able to also share the culture settings - to change culture in one app should also change the culture in another. Currently, we can get the current Kentico culture in the external app. Is there a way to change Kentico culture settings through the API code?

Thanks, Petr