Project A has a time to first response of 1 hour. Project B has a time to first response of 30 minutes. A ticket is created in Project A and the SLA starts counting down. After 15 minutes, the ticket is moved to Project B. The SLA does not reset, which means it's now 15 minutes into a 30 minute timer. 

When a ticket is moved from one service desk project to another, SLA's should be reset, just as if the ticket was newly created in the destination project.