ETS offers rescheduling and cancellation options for GRE test-takers.
If you need to reschedule your test, you can do so up to 4 days before your scheduled test date. However, a $55 rescheduling fee applies.
For cancellations, ETS allows test-takers to cancel their test up to 4 days before the test date. For example, if your test date is scheduled for July 10, you must cancel by July 6 to be eligible for a partial refund. If you attempt to cancel after this deadline, you will forfeit the full test fee.
All rescheduling and cancellations can be done on the ETS portal.