You can schedule an exam in Tamil Nadu either online or by phone. If scheduling by phone, you'll need your Authortization To Test (ATT) number on hand, as well as other information to confirm your identity.
You can reschedule your exam in Tamil Nadu either online or by phone. However, in order to reschedule an exam at an "international" testing center, you may reschedule by phone only. "International test center" means a testing center outside the country you seek licensing in.
Rescheduling your exam must be done at least 24 hours before the scheduled time. If your exam is scheduled for Saturday, Sunday or Monday, it must also be rescheduled by Friday.
If your testing center closes, you should get an email letting you know how to reschedule. You shouldn't have to contact them to find out! To make sure you receive these notifications, keep your email address up to date in your testing account and whitelist the emails from the testing center.