Note: You cannot change the Messenger notification sound on iOS.

Tap “Show in Notification Center” to toggle whether Messenger notifications appear in the pull-down Notification Center. Tap “Sounds” to turn notification sounds off or on. Tap “Badge App Icon” to turn the unread message count on the Messenger icon off or on. Tap “Show on Lock Screen” to hide or show notifications when your device is locked.

Return to the main Settings app menu and select “Sound & notification. " Scroll down and tap “Apps. " Select “Messenger” from the list of app. Toggle “Block” on to disable notifications.

You can select a shorter interval to have notifications turn back on automatically after a time.