As preached by The Elements of UX, Nine Pillars of Successful Web Teams, and Matt; UX Design is needed in all phases of product and service delivery. Job titles and descriptions formally define what we're entitled to do in the process.
Perhaps, most of us don't have the formal authority to do something about all phases of product and service delivery. An Interaction Designer (in the strict sense) isn't entitled to touch the site strategy, the Interface Designer isn't entitled to touch the abstract design, and so on.
At times when you're the worker who wants to go beyond the job title and/or description in the name of UX, how do you face the challenges?