When configuring your call routing number you may choose to resolve incidents automatically or in case a caller hangs up the phone.
By default calls that have been accepted by an agent will be resolved when a caller hangs up. If you do not want the incidents to be closed, because you might want them to be escalated further you may choose this option to leave the incidents open.
When routing a call routing number based on support hours, you may choose to auto raise the incidents priority (resulting in an additional escalation at certain future point) in case one of your routing options targets the voicemail.
For example: if after office hours you do not want your callers to be routed to agents and instead send them to the voicemail, the incidents of your incoming calls will re-escalated in a higher priority at the beginning of your office hours on the next day - resulting in your agents being notified and no incidents to be missed.