Does Reentry on OPT will impact H1B processing?

Hello Experts,

My friend is on F1 OPT and his H1B petition is picked in the lottery and it is under regular processing now. He is ready to upgrade it to premium but he has to go for his wedding in August to India. He is working currently on OPT. His concern is while coming back to USA in August he should come on H1b or F1 visa? because his H1B will not be active until Oct 1 and if he comes back on F1 then will that impact his H1b? Does he need to go for H1B stamping in India before coming?

Please advise us to know the best way to get through this situation.

Thank you

I assume his OPT runs through Oct.

If his H-1 is approved and then he leaves US, he can return on F-1 and still be on H-1 from Oct 1. This makes assumption that H-1 was approved w/ COS.

H-1 COS effective date would be Oct 1 and let’s say if he returns in Sep then F-1 I-94 date would be Sep 15. So he would remain on F-1 based on F-1 I-94 and will move to H-1 based on H-1 COS I-94. This is called Last Action Rule.

He should also discuss his case w/ his H-1 attorney.