Hi

My husband came to US on H4 visa in Mar 2007. Got his H1b in Oct 2007 with COS approved & started working immediately and has job till now with all valid continuous paystubs. He didnot travel outside yet and has not got his H1B stamped on his passport.

If he has to travel to Canada as an emergency for 2 days and comes back to US with H4 stamping (since approved 797 not stamped) he goes back to H4 Status right?

In this case, after he comes back, can his current employer apply for the COS from H4 to H1 with paystubs? How long does this COS processing take and when can he start working again?

Are there any complications going back to H1 from H4 this way?