Resizing C and D partition on same RAID array.

I've been looking at documentation and some previous posts, but want to make sure I understand what I need to do. 

I have a customer with a Windows Server 2003 server.  They have the C and D partitions on the same RAID array.  The c partition is low on disk space while the d partition has plenty of space available.  I would like to resize the c partition using some of the space available on the d partition.

From what I've read so far, I need to create unallocated space between the c and d partitions, correct?  Since that unallocated space is not there now, I can use gparted to do this first, correct?  Then resize c into the unallocated space? 

I will make sure to have good backups before taking on this adventure.

Any additional help and shared experience will be greatly appreciated.