Quick Steps

1. Download & Install  SharePoint Online Management Shell Module (released on and after November 2017 or newer)

2. Open SharePoint Online Management Shell

3. Connect to your SharePoint Admin Portal

4. Execute the following PowerShell command: 

# get a reference to the site collection where the
# site collection app catalog should be created
$site = Get-SPOSite https://your-domain.sharepoint.com/site-path 


# remove site collection app catalog
Remove-SPOSiteCollectionAppCatalog -Site $site

5. That's it!

For detailed steps, please follow the commands given in our Configure Site collection app catalog using PowerShell article and the only change is to use Remove-SPOSiteCollectionAppCatalog command instead of Add-SPOSiteCollectionAppCatalog