Vacation during job transfer in H1B when I797 is valid

[techkrish]

I currently work for Company A with my I797 valid till April 2019. I transferred my H1 to a new Company B and the new I797 is from 08-May-2017 to 07-May-2020. I got my Receipt on March 23 and approval on March 29.
My current company's last working day is 21 April 2017. 
Below are my questions. 

1) Can I join Company B on April 24 before approved start date in new petition which is May 8 
2) Can I choose to stay on vacation from April 22 to May 7 without being on any company's payroll.

[pontevecchio]

You are generally allowed up to 60 days to report in your situation. Have a chat with the HR of B.