You can create a schedule and add it to a security rule to make the rule active during a certain period, but only once.
The table of one-time schedules is displayed in the Application & Services → NGFW → Objects → Schedules → One-time section.
The table contains the following information about schedules:
Name is the unique name of the schedule.
Description is an arbitrary description. Optional setting.
Start date is the start date and time of the schedule.
End date is the end date and time of the schedule.
Number of days for pre-expiration log is the number of days before the end of the schedule when daily system events begin to be sent to the SIEM system.