I am uncertain what device you are referencing. There are no other current malfunctions reported by your system. Please let us know the model of device you are looking for assistance with power cycle steps.
In general, if you mean on a wireless alarm sensor, open the sensor and remove the battery for 60 seconds. That said, a power cycle is not generally a fix for wireless sensors, and the issue is more likely something described in the post linked below. Replacing batteries can help, but just powering it off and back on generally won’t.
If you are still referring to situations where all sensors report offline status, the recommended steps to try first to address this issue are listed above. Below is a link to the post I am referencing. Have you checked this yet? Power cycling sensors will not help resolve this at all.