Change of Status H4 to H1 : Getting Stamped for H1

[sowjanyacs]

Hi,

When I first came to US ,I was on H4 visa, I then got an H1 B. I have been working since then, but I never got H1 stamp in my passport. I am planning to visit India next month. I have scheduled an appointment for H1 B stamping.
I am carrying all needed documents. I-797, I-129, Employer letters.

1. Is there a chance of my H1 B visa getting rejected?

2. If my H1 B visa gets rejected.
- Can I come back to US using my H4?
- Do I need to reapply for an H1 B to work again in US?

Anyone who has similar scnario, please contact me.Any input is greatly appriciated.

Thanks,
Sowjanya