H1b-221gYellow--convert to H4(return to US)---convert back to H1

[Chanakya9]

My spouse has gone for H1 stamping in Feb 2011 and got 221g Yellow .Even after submitting the documents there is no response from the consulate.

Now I plan to call her back on H4 (she has to go to stamping again as I had an extension).

Would the I797 still be valid once she comes back to the US and will she be eligible to convert her status back to H1 as she never used the H1 before ?.

She got her I797 approval but within 15 days had to leave to due to an emergency.

Guys your suggestions/advice/experiences are invaluable for helpless ppl like me.

I appreciate your time for sharing thoughts in advance.