H1 to H4 and back to H1 (should it be done before expiry of H1B or Petition or 6yrs from approval) ?

USA H1B Visa
1

Case: I am on H1B and changing to H4. I consumed only 1yr of H1B time.If I again want to get back to H1B.

Question:

What are the rules regarding max duration after which I can switch back to H1B

I should switch back :-

a) before Expiry of H1B (i797 i held)

b) before 6 yrs of orignal H1B Petition approval date

c) any number of years after switching to H4

2

You are cap-exempted for 6 years from the last day of holding H-1 status. Let’s say you move to H-4 on May 1, 2016; then you are cap-exempted until April 30, 2022.