L2 to H1B - without traveling out of US

[buzzpriyav]

My wife was working on H1B for 3 years from 2009 to 2012. She wanted to take a 1 year break from work and hence did a change of status to L2 (I am on L1).
COS got approved in Sep 2012.
Now she wants to get back to work using the same H1B (which was approved till end of 2014).

1. How can she get back to H1B status? Will the old petition still be valid or should she apply for cap exempt?
2. Should she get a stamping freshly? If so, should she travel to India?
3. One person told the change of status from H1B to L2 would have invalidated the H1B petition. Is that true?

She is not opting for L2 EAD.

Please assist.


-- PV