Employee wants off of Exchange. Can we go back?

One of our managers was put on a Microsoft Exchange account when she went on Maternity Leave, and now that she is back is having major issues with speed. It's 100% her Outlook causing the issue. I've updated her Office to 14.3.8 and her brand new Macbook pro is at 10.8+. She is the only one of 20+ staff on Exchange. I've spent several days doing everything I can to optimize it, and nothing seems to work. She is set to only download headers and no folders are over 2000 email anymore. The wheel is spinning over 50% of the time and the scroll doesn't work. It seems to be constantly syncing or sync pending. At this point, the only thing that will make anyone happy is to have her moved back to an IMAP account. 

I can't find anything on this. I realize Exchange is much different from POP and IMAP so you can't just switch, but so what do I need to do? I don't know enough about Exchange to know how better to ask this question, so any background information helps. Any additional resources on Exchange might help too. I've read for hours on what could be affecting the speed, and at this point we just want her off Exchange. 

Help? Thanks for any in advance!