Reminders are a special notification type for events and tasks. In eM Client the reminders can be shown as separate notifications, the same way email and other notifications are, or you can use the Reminders window.
Reminder window settings can be found in Menu > Settings> General > Reminders, find closer explanation here.
The reminders window shows all active reminders for your upcoming (and past , depending on your setting) events and tasks. You have a number of options available in the toolbar to work with these reminders.
Dismiss All - Dismisses all reminder shown in the window
Dismiss - Dismisses just the selected reminder
Snooze All - Postpone all reminders shown in the window - click the button to snooze by the default snooze time or click the drop-down menu to select a specific time period
Snooze - Postpone the selected reminder
Mask as Completed - Applicable to tasks, you can mark the task as finished and dismiss the reminder in one step.
Double-click the item in the Reminders window to open the given event or task in a new separate window, if you need to edit the item itself.
The Snooze buttons drop-down menu allows you to select a time or set Default Snooze Interval which is one of the available time options in the list: