If it has a set of commands such as fly on a certain date to a specific location, then it will carry out those commands. In the recent conjunction it was commanded to take one colour image per day for three weeks. After conjunction it contacted the rover and sent the images over a period of a few days. If it has no commands it will stay in survival mode, charging its battery and running it’s heaters overnight so it keeps its electronics etc warm. Each day at a set time it will try to call the rover. Meanwhile the rover will listen at the same time. This was actually when they lost contact for many weeks after the helicopter made an emergency landing. Many weeks later the rover had moved to a location where they could resume comms.