L1B to H1B Visa COS start date as the H1B approved after oct 1st

Currently I am workng for company A on L1 in USA, I have filed for H1b through Company B and petition is approved with COS on 12 feb 2018, if i want to continue in Company A with L1, what are the option i have to do so.

My Company B is ready to withdraw my h1b petition, do i still need to travel outside USA and comeback on L1 status?