How to cancel an announced Android System update I wrongly click the button to book a update for Android System.
How can I cancel it before Nov 22 after 02:00
You can not cancel the update itself because it has already been applied.
Modern Android devices have the system partition twice (called A/B partition). One that is currently active and one that can be used for installing updates &quot;seamless&quot; (so called by Google). Which partition is currently active on next boot can be changed.
The screen you show means that an update has been downloaded and installed on the non-active partition. The only step left is rebooting into the updated partition.
I am not sure if you do the reboot but not switch to the updated partition. No matter even if you would manage to do so I assume that the system would start to download and re-apply the update again on the other partition and then ask for rebooting into it to finish the update.
Prevent updates via Developer options
Edit: Even if it is too late for you I stumbled over a settings that might be helpful in similar situations:
On a Pixel 3a running Android 11 I saw in the Developer options and entry called Automatic system updates - Apply updates when device restarts
Therefore if you have such an option and disable it while there is already a pending update plus a scheduled reboot you can cancel the update installation.
If you decide later to install the update you can do that by manually triggering it in the Android system settings.