No, it is not a problem as long as you maintain your H1-B status. Whether you have changed employers or are in the 60-day grace period, she can return on her H-4 visa without any issues. Even if her visa stamp bears the old employer's name, it does not matter. There are no specific steps to take in this situation as it is perfectly legal.

The green card remains valid as long as you don't exceed the 12-month mark. Crossing this deadline leads to losing the green card and going through complicated procedures to retrieve it. If you stay outside the US for more than six months, you are subject to close examination by Customs and Border Protection at the airport. However, if your absence is less than six months, you can pass without being questioned extensively. The critical six-month mark should be taken seriously. If you stay outside for more than eight months, expect to be asked questions about the reason for your lengthy absence. Therefore, carrying evidence supporting your reason, such as selling your property or helping a family member, can be useful.

To make a strong case, it is not just about the number of recommendation letters, but also the quality of the letters. A ballpark estimate for the number of letters would be around 5 to 10. Quality is definitely more important than quantity. When considering recommendation letters, people who know you by reputation rather than just personally are given more weight. It is important that the letters are detailed, with specific reasoning about what makes you special and why you are in the top 10%. The qualifications of the people writing the letters, including their resumes, should also be included. The validity of recommendation letters can become questionable if they are too old, so it is better to obtain recent letters if possible. However, if there is a choice between getting an old letter or no letter at all, it is better to have an old letter. If the letter writer cannot write on official letterhead, they should include a line stating that their opinion is not that of their employer.

When filing for the permanent labor certification (PERM) application, it is important to file from the corporate headquarters instead of a branch or sub-office, especially for consulting jobs or jobs that can be transferred to different locations. This is because the U.S Department of Labor considers the corporate headquarters to be the job site for transferable jobs. After the I-140 is approved, the priority date belongs to the individual even if the I-140 is withdrawn, unless it is revoked for fraud, misrepresentation, or an obvious error. Additionally, as long as the I-140 stays approved for 180 days, the individual has the right to extend their H-1B beyond six years with any employer, even if the I-140 is revoked. After 180 days, the employer can revoke the I-140, but it does not affect the individual.