H1b Visa transfer to new company before moving ton USA

HI All,

i’m working for an ABC employer and My H1b picked recently, approved by USICS and visa stamping is only pending. After visa stamping can i move to new employer like XYZ with previous employer H1b visa before moving to US? is there any chance new employer will take benefit and sending to US instead of going again H1b Lottery.

can i use same H1b moving to new company before going to US or it is mandatory to go US and move from there ?

please help me on this

Thanks in advance