i highly recomend that you postpone your travel until the change of status to H1B is finalized. You just want to eliminate any confusion or risk in the process of COS while you are out of the U.S.
Elkhalil Law, P.C.
Disclaimer: This answer is for informational and educational use only. This answer does not create attorney-client relationship. For more details, I recommend a private consultation with an immigration lawyer.
The safer way to do your H-1B can be "petition only". After H-1B approval, you can go to a US consulate to get an H-1B visa to come back to US. This way, you can travel, if you have to travel.
The first thing is that if you have an attorney handling it, then this is a question to be posed with that attorney. This is the reason you hire an attorney. However, without going into detail, if the H-1B application is pending when you depart the United States (which seems likely) then DHS takes the position that the request to change status is abandoned. The H-1B petition can still be approved, but it should be consulate processed (I assume after October 1).