Go to “plot”, then where it says “page setup name” click “add”, select your page setup and then click “delete”
OR u have to write a vb code, which u try the below:
Public Sub DelPConfig()
Dim objPlotConfigs As AcadPlotConfigurations
Dim objPlotConfig As AcadPlotConfiguration
Set objPlotConfigs = ThisDrawing.PlotConfigurations
For Each objPlotConfig In objPlotConfigs
objPlotConfig.Delete
Next
End Sub

Hope it helps u !