stamping in tijuana and US visa stamp will expire

[e_babe198027]

I have worked in company A for few months but resigned and currently working in company B, i have valid H1b's on both companies, but company A is the only one stamped on my passport and will expire April 30, 2011. Im planning to go stamp the other H1b in tijuana this early march, i have few concerns:

a. Do i need a mexican visa to FLY to tijuana if i want my visa stamped?
b. What if my request for visa stamp is denied, will i be able to re-enter US a month before April 30 (expiration)?
c. What if I go to my home country for a short vacation around feb, will they allow me to re-enter US without stamping the new H1b visa? THe old one is Ok til april 30, 2011. How long is the time they will allow for me to travel outside US prior to expiration april 30, 2011.

thanks

[txh1b]

a. For flying you might need visa. Suggest you fly to San Diego and go by road for which a visa is not required.
b. Depends on if your visa is stamped CWOP before the interview. My observation is the VO stamps CWOP while interviewing. If that happens, you cannot enter.
c. You can enter anytime before expiration of visa and show your new company I797 at the POE with old visa. No issues.

[e_babe198027]

a. For flying you might need visa. Suggest you fly to San Diego and go by road for which a visa is not required.
b. Depends on if your visa is stamped CWOP before the interview. My observation is the VO stamps CWOP while interviewing. If that happens, you cannot enter.
c. You can enter anytime before expiration of visa and show your new company I797 at the POE with old visa. No issues.

I dont understand "B".
what is CWOP and VO? cuz my visa is still valid until april 2011 and my new H1b is valid until 2012, the one that i will stamp in tijuana. Now if i go there feb and they deny my new stamp can i get back to US with my april 30, 2011 visa

[shervin143]

A simple google search would have given you the result for CWOP - 'Cancelled without prejudice'. When you go for visa stamping, sometimes the VO (Visa Officer) might stamp CWOP on your exiting visa, in which case you cannot re-enter U.S as the visa is been cancelled.