[Itsm] Problem/Incident tickets with SLA

Hello, I have a question about a problem or incident ticket that has a service with SLA attached to it. In the SLA I specified the "First Response Time", "Update Time" and "Solution Time". If "First Response Time" is less than two hours from the current time than you get a notification in the QueueView telling you something must be done, all that is perfect :-) My question is how do I change the status of a ticket so that it knows that I responded within the time? I tried locking, unlocking, setting the Additional ITSM Fields but I keep getting the notification in the QueueView untill I close the ticket. Thanks in advance!