Question: Can anyone please clarify when the H4 application is going on, would the applicant able to stay in the USA based on the ongoing application or have to leave the USA and come back when the application is approved?
H1B to H4: Status While COS is Pending
To change status inside the U.S., you must now maintain your current status up to the change of status approval; technically they say maintain status up to 30 days before the change of status approval, but since there’s no way to know when the approval will come, then basically status has to be maintained throughout.
If status cannot be maintained, then leaving the U.S. would be the best option, but would also abandon the pending COS application.
An approval from USCIS for H-4 would only be valid inside the U.S. Once you leave, you still have to appear for the H-4 visa interview.
You would simply take the H-1B approval to apply for the H-4 outside the U.S. The H-4 approval from USCIS isn’t used at all at a visa interview.