[1] Open Phone Dialer and enter *#*#3646633#*#*.
By entering this you will enter 'Engineer Mode' of the device.
Note : "Misconfiguration in engineer mode can cause damage
[2] In engineer mode go to CDS Information
[3] Click on Radio Information
[4] Select Phone 1 for Ist imei (Phone 2 for IInd imei)
[5] At the top on command line type EGMR=1,7,"IMEI" after AT+
please type 15 digit valid 1st imei number within quote " as shown
here : AT+EGMR=1,7,"1234567890XXX15"
[6] Hit send command
Don't put imei without quotes. Wrong way: AT+EGMR=1,7,1234567890XXX15
Correct way: AT+EGMR=1,7,"1234567890XXX15"
please put imei between " "
Don't Ignore Special Characters
[7] For 2nd imei number type after AT+EGMR=1,10,"IMEI_2" (put your 15 digit 2nd imei number in place of "IMEI_2"
[8] Hit send command
[9] Reboot