There may be a scenario, where we would need to uninstall the horizon instance. For that, we would require the same tool can be downloaded from https://dev.sitecore.net/Downloads/Sitecore_Horizon.aspx
We have chosen for our instance as
Please add the below variables in the same file
[string]$PhysicalPath = $horizonPhysicalPath,
now please comment InstallHorizonHost method calling and add below as per screenshot
Import-Module "$PSScriptRoot\InstallerModules.psm1" -Force
Uninstall-HorizonHost `
-InstanceName $InstanceName `
-PhysicalPath $PhysicalPath
Once done, run the PowerShell script. Horizon instance will be uninstalled.