I don't know your expiration date of current B - 回复：B-status and

so you may need to consult an attorney accordingly.

1) if your B is denied, you may need to leave US right away, or your are subject to be out of status prior to your H-1 effective date

2) if your B is granted, your H-1 maybe revoked because of that newer approved petition

If you don't have a petition pending, and your current status does not expire until after your H-1 effective date, you do not leave US to "activate H1B".