How to replace the Announcer Sound from saying Roy, to him saying Riku:

in Mex tool, open your iso>

on the left side, click "Sound" > Under "Sound Banks:" select "Sounds" from the two options above "Scripts[Sounds]" scroll down to "51. nr_name.ssm">

In "Bank Name: nr_name.ssm" scroll down to "12. Mono: 12000Hz ..." click it> 

then click the circular arrows icon right below "[Sounds]" replace sound.>

navigate to the wav file named "12" from this download and select it, press enter

save your iso