I got H1B stamping in May16 &hold valid I797.didn’t get chance to travel till nw.wht is d process to transfer?

I got H1B stamping in May16 &hold valid I797.didn’t get chance to travel till to US. Now my employer is trying to withdraw my H1b. What is the procedure to transfer the visa and if I travel now what is the problem I can face in Poe?