Need info on Visiting Visa!!

[madz]

Hi,

 

My Mother has a B1/B2 visa, which will expire in Oct (she initially got her B1 visa for 10 years and will be expiring in Oct).

 

I would like to know whether or not B1/B2 visas can be renewed
*before* expiration, and if they can be renewed *before* expiration,
how far in advance of the visa expiration date can they be renewed.

 

Appreciate your suggestions.

[ashuneel]

6 month in advance.