Please help!

I am currently working in GE. Got an offer from GE's another business unit, and I have faxed the acceptance letter. Minutes later, I got another offer from outside. This offer is much better.

Can I withdraw my acceptance to GE's offer? Right now, GE has not started the relocation since they disagree with my start date I have put in the acceptance letter.

If I change mind, what is potential consequences? One consequence could be that I can never come back to GE.


Any ideas? Anybody has similar experience?

Thanks