Open a terminal or use a modem management tool (like those in GL.iNet or OpenWrt interfaces) to access the AT command prompt.
You're looking for information on changing the IMEI of a Fibocom L850-GL module. fibocom l850-gl change imei
In many regions, changing a device's IMEI is illegal or a violation of your carrier's Terms of Service. Always check your local laws before proceeding. Do you have a specific laptop model you're working with, or are you trying to bypass a carrier restriction xmm7360/xmm7360-usb-modeswitch: Tools for the ... - GitHub Open a terminal or use a modem management
Incorrectly applying commands or firmware can permanently disable ("brick") the modem. fibocom l850-gl change imei