Time Windows for Interview Appointment

[traveller2us]

Hi,
My wife is applying for an L2 and got an appointment in Chennai in March 2007.

We are looking to reschedule her appointment.

• What are the best time windows to lookout for in the vfs portal?

• 
  Is there any other way to get a earlier interview?

Please help folks.
Sincerely,
traveller2us