How to Update the new I797 details with USCIS?‘

Hi this is Krishna and reside in US. I had applied for H4 4 months back and I was waiting for finger prints…Mean while my Spouse who happens to be on H1b changed job, took a new position at another company and she got 3yrs of extension. Now the question is ‘How to update the new I797 document / details with the USCIS?’

Well, you could send in a letter to USCIS indicating the details of new H1B petition. They may or may not consider, it is up to them.
Alternatively, you can file a new H4 extension using the new one, that will give you full term.