Dear ... 
I have been working with __(Name of Organization)__ for __(length of time)__ now and can honestly say that I’m proud to be associated with this organization.  Over the past __(length of time)__, I have taken pride in performing the duties of __(name of position)__, which is a responsibility that I take very seriously.  I’ve embraced the challenges in this role and have managed to successfully work through each of them.  My job here is a rewarding one. 
A situation, however, has recently occurred leaving me feeling both confused and unsettled.  On __(date)__,  __(briefly describe what happened – example:  a memo went out that stated…..)__.  There was no communication with me regarding this change prior to that __(memo/incident/etc.)__.  As this directly affects my current duties with __(Name of Organization)__, you can imagine my surprise and confusion to find out about __(this change/theses changes)__ in this way. 
In looking at my performance record with __(Name of Organization)__, I see that there have been only positive reviews, leaving no clues as to why __(briefly explain what has happened)__.  Hence, the reason for my letter to you today.  I am asking you to kindly provide me with an explanation as to why events have unfolded in this way. 
__(Name of Organization)__ has, up to this point, treated me very fairly and so I remain hopeful that there is a reasonable explanation for this.  Thank you for looking into this, __(Name)__.  I look forward to hearing from you soon. 
Respectfully yours,