Can Non-working reasons be reconfigured?

Using Oracle Field service core application, our users want to be able to select how much time will they be on sick leave or annual leave (this are Non-working reasons under shifts). When I look at these on the configuration page and click on edit I see you can only edit the label or name of it but I am not sure where is the configuration to select the amount of time it will block the calendar for. Is this not editable?

As an example, let's say I get sick tomorrow but at noon, so if I add a sick leave non-working reason, it blocks the whole day as non-working but I have already worked 4 hours and only want the last 4 to show non-working.