There are at least three different usages of singular they. The newest is where a specific person for various possible reasons has asked to be referred to in that way. The oldest usage is where the referent is unknown or generic. E.g. &quot;The technician sent by the company isn&#x27;t here yet, they may have gotten stuck in a traffic.&quot; Finally, some people use singular they even where the referent is specified and that person hasn&#x27;t expressed a preference for singular they. E.g. &quot;President Obama is on vacation, they must be tired after dealing with ISIS all last week.&quot; I find this last usage jarring.