This process is very simple, let’s do it together:
In the left side menu, look for the module called: Publish and click on it.
Inside this module in the top center you will find a button called: History. Click on it.
Here you will find the list of all the publications you have published, scheduled and saved as a draft. Select the publication that is of type: Scheduled and is in Unpublished status.
In the Actions column on the right side, select the Cancel button.
And that’s it, your schedule has been canceled and will not be published.