This is actually two different things in K2 (although they would seem to be related).

You can set the Expected Duration by right-clicking on an event, left-clicking Properties, then going to the General Properties tab.

To send an email notification after a certain time, you need to use escalations (start here).

Note that these two items function independently of one another.  You do NOT need to set an expected duration for an escalation to work (and vice versa).

Hi sbrownhuntoilco,

Thank you so much..  it's working perfectly