Retrieve a single Visitor record by its Id.
Authorization header.
The authenticated user must be a full unrestricted administrator or have the Visitor-Read role.eVisitorSource enum values: 1 = Administrator, 2 = NexIO, 3 = Customer.eVisitorHostApprovalStatus enum values: 1 = NotRequired, 2 = Requested, 3 = Rejected, 4 = AcceptedAndHold, 5 = AcceptedAndGrant.