H1B Transfer

[kkbm]

Hello,

I have a question regarding H1B visa transfer . I have H1-B visa and working for employer A . I got a offer from employer B and my visa transfer is completed and approved for employer B but I have not yet joined employer B . Now I get better offer from employer C . I would like to join employer C .

Is there any legal obligations in joining employer C ? . Do we need to get any approval from employer A and B during visa transfer to employer C?

Regards,

Kiran.