When switching between Pilot Assist and adaptive cruise control, you enable or disable steering assistance. While adaptive cruise control is considered a sub-feature of Pilot Assist, the main difference is that Pilot Assist can provide steering assistance whereas adaptive cruise control cannot. Therefore, switching between the features can be viewed as enabling or disabling Pilot Assist's steering assistance.
Important
While the conditions and limitations are similar between Pilot Assist and adaptive cruise control, it is important to know the differences. Make sure that you understand how switching between assisted driving features affects your driving and the car's behaviour.
Press the switch button 
on the steering wheel.
Your selected level of support is shown in the driver display.