Default flashing to different carriers

ive been searching and cant find much so my question is, is it possible to flash the verizon sch-i515 to a different carrier who supports 3g cdma? i dont want to buy this phone if it is not possible and im about to get it for a very very low price.
AT&T LG G2(Black)-SOLD
AT&T LG G-Flex-completely stock
"Its not the device....its operator error."