Expand a local De-dup Folder

We are runing BE2014 on Windows 2008 R2 with a single media server. The De-dup folder is on a NTFS partition with cluster size default to 4 KB of size 13 TB. It's limited to 16 TB max but we need to expand it over a new storage expansion of 27 TB.

So how can we overcome the limitation to create a new De-dup folder with total capcity of 40 TB without losing any existing backup sets?