How to change the time of or delete a custom scheduled scan?

Hey - Before the great purge of scheduled scans to the nether regions of the settings I scheduled a scan to happen at 6pm every sunday, but this is too late as it doesn’t finish before I go to bed if this is early (I have 3.5TB of data and it’s reading file contents). So I want to change it to start earlier, but there doesn’t seem a way to change it, only to schedule a new scan type, which wouldn’t help as the current one would still run. Either that or if there was some way to delete it that’d work too as I could create a new one with the new time, but that’s suboptimal.
Thanks

Hi, a clean reinstall of Avast will fix it.

could you be a bit more specific? fix what in what way?

See: https://forum.avast.com/index.php?topic=226747.0

Clean Install of Avast:
https://goo.gl/4Ptzkf
If you need additional help with the Clean Install, watch this:
https://youtu.be/p-h3myRD51A

Yes, a clean install resets everything.