Change workflow state via API

I checked through the API document and realized that there seems to be no function to call to change the workflow state for a specific document.

The purpose is I want to build a simple mobile UI for the end-user to interact with the workflow without going into Mayan. Mayan UI works well on desktop but on mobile where the user cannot change the state using transition, because they cannot tap on it.

If anyone knows how to achieve this, please help me.