can I switch employer on H1B approved petition, before stamping ?

I was on L1 (which ends on June 9, 2013, L1 B ext denied on Oct 17, 2013). H1 approved on Oct 15, 2013 but I94 didn’t come with I797 A, so I had to come for stamping. Now my employer is not able to find any job for me (he is searching corp to corp, but no interview happened till date). Can I switch my employer (just on approved petition ) current employer send me scan copy of approved petition till 2016.

Now my employer is asking me to come to US on visiting visa then he will file Visiting to H1 conversion (he is saying, I need not go for h1  stamping in that case). He is not getting Client letter.

Please suggest.

This looks like a duplicate of another question that I answered.