Is visa restamping needed?


I know this is very common question being asked. But my situation is:

I came to US on H1B sponsored by employer A from India. H1B petition was valid till September 2016. Visa and I-94 is also valid till September 2016. After coming here, I changed my employer and now have new approved H1B petition but it is valid till January 2016 which less than my old H1B petition with employer A. I am going to India in June 2015 and returning in July. So do I need to do restamping or can I enter in US with old but valid visa?

I appreciate your help!!

If the previous visa is unexpired you can use it to enter with offer letter/797 etc. Personally I think its always better to get it stamped as everything is clear at that point.

H1B visa are per petition basis. If you leave US now, before coming you need to have visa where petitioners name is Employer B. And all the good things like proof of employment, paystub, i797 etc will be required for PA.