I-94 Stamp to be Changed

[VisaHelp1]

Please suggest me on the following:

I ihave both L1 and H4 visas stamped.
I'm here in US with H4 petition. I need to go back to work status and for this my I-94 has to be changed.
Options can be :
1) Can I visit any local USCIS office and ask for a new I-94 stamp with my L1 petition.
2) Can I visit Canada and come back to US ...showing my L1 petition.

Please let me know if the first option can work out.

Many Thanks.