I am working on H1B visa. I recently got an offer from a Company A, I signed there offer letter, scanned it and send it back to them. The company has filed my LCA and shall apply for H1 transfer after LCA is done.

Now, I got an offer from another company B, which is far better than the first one and I want to go for this one. My question is, since I have signed the offer letter of company A, and they have filed my LCA alread (H1 transfer not started yet), can I withdraw from it, and ask them not to do my H1 transfer, and join Company B instead?