Hello my name is ***** ***** I am delighted to answer your questions today. I have 35 years experience as an immigration lawyer.
As long as you have an approved H1B the former employer cannot withdraw your wife's status. It is not based on your petition with any specific employer but on you having an approved H1B status with any employer. The employer has no authority to withdraw a application filed by your wife. It is her application and her signature.
If you want total peace of mind your wife can file an extension using form I-539 even though she may have an I-539 pending, she can file a new I-539 based on your new extension with the new employer.
She can do this on her own and provide a copy of I-797 approval notice for the new employer. That way she will have an I-94 with the same expiration date as yours and it is easier to keep track of.
She need to include a copy of your and her biographic page of passports, copy of any visas, copy of your and her current I-94 and a copy of your latest I-797 approval notice with your extension and the filing fee.
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