Reentry in US for new I-94?

[shinjans]

I am in the US (in California), working for Company A. Now, Company B filed for a petition and got a new approved I-797. However, due to some miscommunication, they didn't do a 'extension of status' but a new premium processing filing. The attorney of Company B said that to join company B, I would need a new I-94. I was suggested to step out of the US and come back and get new I-94 at the port of entry against the new approval document.
My question -

1. Can I get a new I-94 in a Deferred Inspection Unit (Los Angeles Airport being the closest one for me) or any CBP office?
Or
2. Can I get a new I-94 from Tijuana border? If so, can I just exit US and enter on the same day? Or do I need to travel back to my home country and come back? Please suggest.

Thanks.

[shervin143]

1. Can I get a new I-94 in a Deferred Inspection Unit (Los Angeles Airport being the closest one for me) or any CBP office?
>>> Nope. You will need to leave the country and re-enter. You should re-enter back on a valid H1B visa and you should show the approval notice of the employer with whom you are planning to work at the POE. The I-94 given will be associated to that employer's petition.

Or

2. Can I get a new I-94 from Tijuana border? If so, can I just exit US and enter on the same day? Or do I need to travel back to my home country and come back?
>>> If your visit to Canada or Mexico is less than 30 days, they can ask you to keep the same I-94 which you currently have and will not issue a new one. In that case, you leaving the country is useless. If you do not want to leave the country, then the employer can file an amendment to get an I-94. Once approved you can work for that employer.