It so happens that you need something to be done at a later point of time. Spiraldesk provides a way by you can add scheduled tasks and set reminders for it.
On the left panel, you will find a link which says Tasks.
Once done, fill in the details to execute the task.
Converting ticket to a Task
Navigate to a ticket and find the button which says SCHEDULE.
Once done, you will see a form which is similar to the Add task screen.
Feel free to enter your data and submit !!