Change of employer in E3 Visa (Australian Citizens)

[PK1705]

Hi,
I am a citizen of Australia working in USA under E3 visa for X company. I got a new and better opportunity with Y company. My new company is happy to sponsor me through LCA and Job offer. I came to know that visa transfer while working in US may take up to 90+ Days in which case my new employer will not wait for such a long duration. Until then I cannot work for new employer. So I was advised to apply for new E3 visa from Y company. Go to Mexico to attend the consular interview and then come back to US with new E3 Visa. I am not sure whether I will be granted with new visa. So I do not want to loose the present opportunity and will not inform my employer until I get new visa. I need to give notice period and work for my present employer after getting new employer visa. My questions are:
1. Can I still work for my old employer after I get my new employer e3 visa as I need to serve the notice period for my old employer?
 Please advise. Thank you in advance..

[KK7878]

You cannot work for old employer after getting new visa as old visa is cancelled when new visa is issued.