h1b transfer before visa stamping

This is the first time I’m applying for h1b. My I-797 petition has been approved but the embassy issued a pink slip asking for more documentation, which I’m exactly not sure whether my employer will provide or not. In such a scenario, can I get my visa stamped through the same petition but thru another employer who is willing to support for my employment with the relevent documentation & if so, can you pls let me know the procedures involved.