A new member of staff joined my team seemed to fit in initially I am in a senior position and she was informed that she was there to assist me. What happened is on my one day off instead of discussing any issues with me she went straight to superiors. As a result been given new role in which is has clearly outlinedin a letter that some responsibility has been taken away from me. Therefore as my superior informed me you can talk any time off the record I said am I being demoted and received a written letter from hr informing me that there has been personal complaints made and I am seen as a senior member of staff. I feel like I have been stabbed in the back not only by a member of staff but by a superior who I went to to ask a question about something I was unsure about. I'm asking for advice how shall I play this one should I talk to the member of staff about her work ethic which is underhand and what are your thoughts on the situation?