Probably a matter of personal style, but I wouldn't put public variables in a Class module; I'd use Property Let/Get

Class module Class1

Option Explicit

Dim m_Ary() As Variant

Property Let A(A1 As Variant)
    m_Ary = A1
End Property

Property Get A() As Variant
    A = m_Ary
End Property

Sub DoubleIt()
    Dim i As Long
    
    For i = LBound(m_Ary) To UBound(m_Ary)
        m_Ary(i) = 2 * m_Ary(i)
    Next I

End Sub


Standard module

Option Explicit

Sub test()
    Dim c As Class1
    Dim i As Long
    
    Set c = New Class1
    
    With c
        .A = Array(1, 2, 3, 4)
        .DoubleIt
    
        For i = LBound(.A) To UBound(.A)
            Debug.Print .A(i)
        Next i
        .DoubleIt
    
        For i = LBound(.A) To UBound(.A)
            Debug.Print .A(i)
        Next i
    End With
End Sub