Changing a drive to FAT32

I was asked if I was able to re-partition a laptop’s hard drive due to a lack of space on drive C, as currently it is partitioned into three 2GB partitions. The laptop is running Windows 98.
Drive C is nearly full, drive D has about 1GB of space left and Drive E is virtually untouched with 2GB free space.
Currently the file system is FAT (which I assume is the 16 bit file system). I would like to convert the file system to FAT32 using the Windows 98 Drive Converter (FAT32) command but I’m concerned about the information that is on drive C. Does this utility leave all information intact or does it require any formatting? The laptop belongs to my Managing Director so I need to be sure!

Thanks