how to unlock bootloader

Port : Fastboot Mode
Baud Rate : Not Applicable
Device : Motorola QCOM
Operation : Unlock Bootloader (Fastboot)
Searching for Device in FastBoot Mode… OK
Reading Phone Information…
Model : XT1056
Boot Ver. : 30B7
Baseband : Variable not supported!
Software : Blur_Version.212.144.2.ghost_sprint.Sprint.en.US
IMEI : 256691470706296216
CPU : MSM8960 Pro CS
RAM : 2048MB Hynix S4 SDRAM DIE=4Gb
EMMC : 16GB Toshiba REV=06 PRV=01 TYPE=17
BL Code