How to slow CPU to half

How to put XIAO ESP32C3 into modem sleep as per the document:

Modem-sleep mode: The CPU is operational and the clock speed can be reduced. Wi-Fi baseband, Bluetooth LE baseband, and radio are disabled, but Wi-Fi and Bluetooth LE connection can remain active.

Can reduce power even more if CPU is slowed to half.

How does a person do that? working in the Arduino platform.

To answer my own question. I found when compiling my project there was an option to slow to 1/2 cpu speed and more. Normal is 160mhz {wifi) there was another option 80mhz (wifi). Under normal speed 160 it used 36ma but when recompiled to 80mhz it now uses 27-28 ma. I don’t need the faster speed and saves about 27% power on the battery.

You will find this option tools > CPU frequency.
I noticed there was an option to lower flash memory from 80mhz to 40mhz but it did not have any affect on power.

Hope this helps someone.