How to sand down grip

[Goduster]

I recently had a rod built but the handle is Way to large(thick) compared to the factory handle but was told by builder he could not turn down because it could not be chucked up.So can I take sandpaper and sand it down myself if so what grit,because it won't get used like it is now.

Appears to me that you told the builder you wanted it slightly larger than the factory grip.