How to change "Preferred Network Mode" using adb without reboot?

I'm trying to change my phone's (CM 12, Stock 4.2, both rooted) preferred network mode from "GSM/WCDMA" (0) to "WCDMA only" (2) and vice versa (there can be other modes too), using command-line only. Based on this answer I can make relevant changes into Settings.db using the commands:

adb shell 
su   

settings put global preferred_network_mode 2

However, I can't figure out from the logcat which or how many broadcasts do I have to send and with what extra key values. It is because of it I have to reboot my device to have the changes take effect.

Ultimately, how do I change the network mode without the reboot using command-line only?

Edit: Using aforesaid command in combination with airplane mode isn't working either.