Yes, these expressions can be adjusted real time through the app or scheduled through the app with the events creation. When you create a new event, you can click on Face and select the expression. You can also modify manually the expression with the app.
You can change the face of REMI live on the central tab of the application by dragging it to the right or to the left. Your smartphone and your REMI must both be connected to the internet for this to work.