can work with h1b receipt number for new company

my friend has current situation, does she eligible to work on new company with receipt number?

She is working for company A in US with H1B petition ends this month, and her i94 expires on mid of next month.

She joining for company B and they applied H1B petition in regular processing.

Now does she move to company B with receipt number and start working?

Does she require approved petition to eligible to work?

Please suggest what would be proper steps to work in company B?

Yeah… If she already received the receipt number from company B, she can start working without any issues. In this scenario, since she already received the new receipt number now need not to worry on the previous I94 expiration or H1B petition until she receives the final update on the new H1B from company B. She might have a problem only incase is she gets any RFE or Rejection of that petition from company B. But chances are very very less.