How to overide and set a numeric value?

This is a sensor:

sensor.schlage_allegion_fe599gr_wireless_door_lock_alarm_level_2

There are no services in Home Assistant to set a sensor’s value because a sensor normally represents data received from a monitoring device.

However, there are ways around it as long as you understand that they can only set the sensor’s value temporarily. Whatever value you set will be overwritten either when the sensor receives new data from the device or when Home Assistant restarts.

Try this:
Screenshot from 2020-11-23 13-32-36

If you need a service to do it then rodpayne has created a python_script: