A canceled test is not a completed test for the DOT return-to-duty process. A driver may not return to performing a safety-sensitive function until you receive a negative return-to-duty test result. Another return-to-duty test must be scheduled with the testing facility and completed before the employee may return. If the canceled test was a follow-up test, it also must be rescheduled. You cannot substitute any other tests (random, post-accident) that you conducted for this follow-up testing requirement.