Hi Sankiti,
SLA retroactive start is since when you want to start the SLA.
For example different priorities have different SLA. Let say P1 has 4 hours of SLA and P2 has 8 hours of SLA.
If you change the priority from P1 to P2 after 3 hours, and you have put retroactive start as created, it will count the 8 hours from created time, not from when you changed the priority.
It can be defined on SLA form where you define .
In Navigation pane SLA Definitions > this will open list of all SLAs, there you can either create new or open an existing one.
On Form section "Start Condition" You will see a check box "Retroactive start" you can check it and decide which field you want to base it on. Generally it is created.
Feel free to ask if you have any further questions.
Please mark it correct and helpful if it helps.
Regards!
Uma
