Lenovo on Twitter: "@IamSakthee Hi! Thanks for writing in. We don't support altering the stock ROM or unlocking the bootloader. If you really want to do it, you can visit 3rd party
How to Unlock Bootloader on Lenovo P2 (P2a42)
How to Unlock Bootloader in Motorola / Lenovo Moto phones ?, How To - HardReset.info