Change Events are a power feature in the PagerDuty platform. A change event is a non-alerting datapoint that can help add context to other events. If a service is alerting, did something change? Change events will tell you. We had Buildkite on the PagerDuty Twitch stream in September to show off their integration with Change Events, and I've recapped that stream as well as some of our docs. 

https://dev.to/pdcommunity/who-did-what-keep-an-eye-on-changes-with-pagerduty-change-events-and-buildkite-40an