You can reassign the incident to the escalation policy which needs to be invoked from within the Incident Details Page
Move over to the Incident Page of the incident for which the escalation policy must be invoked.
Click on the Reassign button and choose the escalation policy that needs to be invoked.
This will also be reflected on the Incident Timeline
You can do this only if the incident is still in one of the two Open states, that is,
Updated 6 months ago