Manage Alerts / Notifications - The all new HTC One® (M8)
View this info to change the notification sound for incoming calls and/or messages.
From a Home screen, navigate: Apps > Settings > Sound & notification.
If Settings is unavailable, tap the Dropdown menu (located in the upper left) then tap Alphabetical. If still unavailable, refer to Manage App Icons.
The Sound profile option (at top of the screen) must be set to Normal to modify ringtone/notification/alarm selections.