In the Ranked party window, if you entered using the “Create Party” function or if you entered using “Find Match” and cancel the search, there is a “Change” button next to the match settings:
This calls up a menu from which you can reconfigure your match search preferences. However, the “Save Settings” button is always disabled:
Your only option is therefore to cancel, so you can only change your settings by leaving the party and this menu appears to be utterly useless at the moment. Which is too bad since it would sure be nice to be able to change those settings without having to go all the way out and back…