ML370G5 drive upgrade

[Northof9]

ML370G5 server with 8 72GB 15K drives in one array on a P400 controller. Vendor who sold it to us only assigned 49GB for the system drive c: and the rest for the data drive d:

C: is full. Need to replace the 72's with 146's or 300's. Is it possible to replace them all and then use Disk Management in W2K8 server to adjust the C: drive portion upward? If this cannot be done is there a published HP procedure to accomplish this?

This is a mission critical server running an ERP software package on top of SQL server so whatever procedure is invoked must work.

Thanks for your input in advance!