I have 'UserForm1' and Module1.
In UserForm1:

Private Sub UserForm_Initialize()
Debug.Print "Initialized"
End Sub

Private Sub UserForm_Terminate()
Debug.Print "Terminated"
End Sub

In Module1:

Sub Main()

Debug.Print "Set UserForm1 to nothing"
Set UserForm1 = Nothing

Debug.Print

Debug.Print "Unload UserForm1"
Unload UserForm1

End Sub

After running 'Main', the result is:
-------------------------
Set UserForm1 to nothing

Unload UserForm1
Initialized
Terminated
-------------------------
This means Unload statement creates a new instance of UserForm before
destroying it.
What makes the difference between Set and Unload?
Are there any other differences between those?