Default MOTO E Unlock and relock bootloader without voiding warranty

Hi
Guys i recently bought MOTO E and I want to know method about relocking boootloader ? and How can we claim warranty again.


As in SONY devices we can take backup of DRM keys before unlocking bootloader so we have warranty.

LG devices flashtool can restore bootloader to it's original condition so no worry.

What about Motorola? is there any method should i know ? How can we have both warranty and unlocked device.