In previous versions of word you could change the way that Ctrl plus Pg dn worked by clicking on the object browser at the bottom of the vertical scoll bar. This facility doesn't seem to be available in Word 2013. Moreover there doesn't seem to be any other way of changing the way the Ctrl plus Pg Dn works.
I use it mostly to scroll a page at a time but once I've used the find function finding the word or phrase becomes the default function of Ctrl plus Pg dn.
How do I change the functions of Ctrl plus Pg dn as I used to do in the past?