I am starting with the Zephyr sample "peripheral": developer.nordicsemi.com/.../README.html
This sample started out with a Heartrate Sensor Service and a Current Time Service. I commented out the include statements in the code for the cts.h and hrs.h
In the prj.conf file I also commented out the line
# CONFIG_BT_GATT_HRS=n
and I changed the CONFIG_BT_DEVICE_NAME
However, the device still shows the old name, and it still shows a Current Time Service as well as a Heartrate service.