Dear
We wish to let you know that __(Name of Organization)__ is currently undergoing a major conversion within its computer system to a new operational software program. This new program will serve to enhance the processing of our __(briefly describe type of function(s) that will be better for customers)__ and we are looking forward to being able to offer you better service in __(that/those)__ area(s) soon.
Completion of the software conversion is estimated to be around __(when)__. Though we realize that our customers will be inconvenienced to some degree while we are in the midst of this conversion, we want to thank you your patience and understanding as we all try hard to work around it. Rest assured, it will have been all worth our while to be able to reap the benefits of this new program.
Thank you again, for your patience and understanding during this conversion period. It is so greatly appreciated.
Yours truly,