SLA violation

Answer:
I assume you would like to know how to calculate SLA time and, consequently, know whether the SLA is breached or not.
SLA clock starts counting as soon as incident is opened. It stops once the incident comes to status - resolved. User still should get an opportunity to confirm the resolution (if tool allow that).
But be careful with that - define, in SLA, maximum time allowed when user should confirm incident resolution (e.g. 48 hours or 72 hours). Otherwise, some incidents will never be closed (users just don't send any feedback).
Read the article "ITIL Incident Management – How does it influence customer satisfaction?" https://advisera.com/20000academy/blog/2016/03/22/itil-incident-management-how-does-it-influence-customer-satisfaction/ to learn more.