Please help me with Extended capacity manager&reformatting.

I've used True image Western Digital edition (2013) to format a 4tb drive in fat32, partitioned 2tb, and used the Extended capacity manager to partition the rest of it (all done on windows XP). I realize now I need everything in exFat format instead. Can I reformat one partition to exFat without wiping the data from both? I have no other drive to move my data to at the moment.
format.com(the microsoft command prompt utility) says that to reformat, the volume would need to be dismounted, and all open handles of the volume would be invalidated, but I'm not sure what this means.