extension of i-91 stay

[drsurinder2007]

my name is sp singh i am on b2 10 year multiple entry visa. i have 6 months stay till sep. i want to take my usmle step 3 in oct . and after that i want to do observership in hosp in florida( i have letter from hosp) my question is
1. should i go for extension for 6 months? or its beter to go india and comeback?
2. i heard that if they deny extension then our multiple entry visa will be nullified is that true? that is my main conceren because i need to visit usa again in dec 2008.
3.what should be my base for application of extension ??(my exam and observership)
thanks a ton in advance please reply sorry i mean I-94 not i-91

[txh1b]

1. Extension is risky.
2. Yes, it voids your visa and future prospects due to overstay.
3. Your Choice.

[drsurinder2007]

how early can i visit us AGAIN

thanks a ton for reply that will be of big help to plan my stay in usa
one more question please i have 10 year multiple entry visa i have 6 months stay in usa. i am leaving next month (sep) can i visit again in nov as ihave letter that i will do observership in a hospital? will the immigration people at usa can deny to give me entery?what document i need to show them at port of entery?
thanks a ton in advance

[txh1b]

Depends on your luck. Frequent visits are frowned upon. But that is better than overstaying. The CBP officer may issue you a shorter I-94 on next visit.