H1B Can I enter US post the date of joining mentioned in Client letter/PO?

[SuddenStar]

Hi,

I had attended H1B visa stamping interview on with a client letter and letter from employee stating that the start date of my project is DateX. I am currently working with another company in my home country that requires me to give a notice period of 3 months to resign from the job. For the same reason,
Q1) Can I enter US on a date after DateX that is indicated as my project start date or will I be rejected at the port of entry?
Q2) If after entering US, I start working with a different client under the same employer, will that be a problem later during my greencard processing?

Thanks in advance for your advise.

[SuddenStar]

Please respond.

[speedracer]

1. yes you can enter anytime after your visa start date. The client letter should be updated when you arrive and relevant details.
2. Hypothetical answer to your hypothetical question : If you arrive in US, you have to update your address. Any change in address should be notified to USCIS and more importantly you need to get an amended petition filed if you are going to switch location. I am not sure if a client change is termed as material change according to USCIS.