H1B extention in process-interview date approaching

[denver_lights]

Hello gurus,

Please see if you have an advise for me.
My H1B is in process at Vermont center and my parent's interview date is approching for visitor visa. Date on the my previous H1 has already expired this week.
What documentation/evidence can my parents show at INS? Would the receipt notice be good enough?

Please advise me on this. I would appreciate your replies.

Thank you.

[dahlia]

I think the receipt notice will be enough.