Exit all subs

Perhaps you mean

End

eg:

Sub one()
Call two
Call three
End Sub

Sub two()
If MsgBox("Quit", vbYesNo) = vbYes Then End
End Sub

Sub three()
MsgBox "Invoked"
End Sub

Without seeing your own code it's hard to pass comment, but using my example - if you run Sub one() and click "Yes" on subsequent MsgBox Sub three() is not invoked (no "Invoked" dialog is generated).

This is the code for the main sub

Private Sub CommandButton1_Click()
    
    Dim click As Integer
    Dim response As Integer

    click = ActiveSheet.Range("Z1")
    
    click = click + 1

    ActiveSheet.Range("Z1") = click
    
    UserForm1.Show
    
    If response = 1 Then
        Exit Sub
    End If
        
    Call NotifyDepartments(click)

End Sub

here is the code for the user form

Private Sub UserForm_Deactivate()

    response = 1

End Sub

how do pass response back from the form to the main sub

You would use the Terminate Event, ie:

Private Sub UserForm_Terminate()
End
End Sub

No need to pass variable back to main routine if you intend to just exit the code altogether.

Be careful of the use of End. It will reset all module/project level variables.

The problem is that the response variable is local to the caller routine.
You either need to use a public variable or a private variable within the userform that you can read.

public variable approach.

Public response As Integer
Private Sub CommandButton1_Click()
    
    Dim click As Integer

    click = ActiveSheet.Range("Z1")
    
    click = click + 1

    ActiveSheet.Range("Z1") = click
    
    UserForm1.Show
    
    If response = 1 Then
        Exit Sub
    End If
        
    Call NotifyDepartments(click)

End Sub