H1 to H4 and H4 visa stamping

Hi,Need your help.My spouse came to US on H4 in 2015 and applied for H1 in 2016. H1 is approved and shes working now, will be quitting her job in march 2017 and going to India to come back as H4 (My h1 petition is valid till 2019). Now when she goes for stamping which i94 should she use? i94 from HER H1B 797 A approval - valid till 2017 Sepi94 from MY H1B/her H4 797 A approval - valid till 2019 June.Request you to provide your inputs. Thanks

I-94 is not required during stamping. Both I-94s should have the same number.

The most recently issued I-94 is the correct one, if asked.