It allows carriers to blacklist stolen or lost phones.
While some online sources suggest codes like #7003# for the Nokia 150 (RM-1190), changing an IMEI number is illegal and can lead to device restrictions. Instead, standard, legal codes are available to check the original IMEI ( #06#), reset the phone ( #7370#), or check the software version ( nokia 150 rm 1190 imei change code