Select the Expire Now icon in the QuickLink Panel. This will make the QuickLink immediately inaccessible to anyone, but retain the necessary assets and settings data.
You can also change the Expiration date by selecting 'Edit' and updating the expiration date in the QuickLink Wizard, then selecting 'Save'.
You can always reactivate a QuickLink by Editing the QuickLink and resetting its Expiration, as well as make any other necessary changes and selecting 'Save'.
NOTE: By Default, QuickLinks expire at the same time of day that they were created (ie. a QuickLink created at 3pm that is set to expire in five days will expire five days later at 3pm)