This is the response I received from KORG USA:
You can reset the Pa900 to the factory state by going to Media, then Utility, and use the Factory Restore command. If you only wish to load the factory styles, uncheck “All” and only check off “Styles”.

I see that you have a Pa700, so this is not going to help you ...
On the KORG web site,the Pa900 shows "SOLD OUT".
Why not write to KORG and see if there is a way you can D/L the factory styles.

customerservice@korgusa.com
support@korgusa.com