Multiple H1B Transfers After Accepting an Initial Offer

seeking advice - H1B Layoff . Say I accept an offer from Company A ( small firm ), and they initiated the H1B transfer process on November 10th. However, say on November 18th, I received a better offer from Company B ( big firm but delay in process ) , who also wants to start an H1B transfer. I'm inclined towards Company B due to better terms.

1. Is it possible to proceed with Company B's H1B transfer even though Company A's process has already started?
2. What are the potential implications of switching to Company B's offer after the H1B transfer has begun with Company A?

Any insights or similar experiences would be greatly helpful