How do I make different email accounts use the default sounds again? On an iPhone running iOS 6.0.1, I used Settings &rarr; Notifications &rarr; Mail to set different "new message" sounds for different mail accounts. Now I want to make all mail accounts again follow the default sound set under Settings &rarr; Sounds &rarr; New Mail. How can I do this? When I change the "New Mail" alert sound, the individual mail accounts no longer change.

I have tried manually setting all the mail accounts to use the same sound and vibration setting as the default. However, they still don't change when I change the default setting.
It's not a direct answer, but by deleting an App, you remove the local cached copy of the emails and don't lose any messages on the Mail server.

This has a side effect of clearing the preference for sounds, so when you add the account back - it now follows the default sounds as set in the UI.