Stopping a node is typically performed by the CANopen master via NMT protocol messages. This is done by the CANopen stack without any necessary actions by the application.
The CANopen stack provides a service function to switch the NMT modes by the application. The following line switches the node into the NMT mode: STOP.
CONmtSetMode(&demo.Nmt, CO_STOP);
The internal behavior of the CANopen stack is shown in the following diagram: