Let us get down to business without wasting time
First, download MTK Engineering mode app here on your android phone.
Then install it on your android phone. Don't forget to first allow installation from unknown sources.
Open the mtk engineer app you just downloaded and click 'MTK Settings'
NB: If the option isn't available or you get an errpr message that 'Engineer mode app is not found', then your phone is not supported becauce the processor is not built by MTK.
Swipe the screen left to 'Connnectivity' tab OR scroll the page down and select 'Connectivity' as applicable to the android version you use.
Next, select 'CDS Information'
Then select 'Radio Information'
Select the sim you want to configure/change the imei (if your phone is dual sim)
If sim 1, type AT+ EMGR=1,7,"_new imei_number"
but if sim 2, type AT+ EMGR=1,10,"_new imei number"
Finally, Click 'Send AT Command'. You should get a message below the screen that it is successful.
See the pix below for clarification:
Restart your phone OR turn on Airoplane mode and turn it back off again.
Voila!!!! There you have your new imei changed.
Good luck to you.
See also: How to use Glo BIS on Android Phone