The default save location of the Phototuning queue is:
Dongle installations: C:\ViSoftCreative\UserData\VRay\ScheduledTasks.
Online license: C:\ProgramData\ViSoft\ViSoftPremium\UserData\VRay\ScheduledTasks
These folders can be copied for a backup of the rendertasks. Or delete the tasks to clean up the folder and create space. If you want to restore the backup, copy the tasks back to the original folder.
If you want to export a rendertask to another computer with extra power, open the context menu and select export task. If you want to import, use symbol icon (marked blue below).