Refresh Data Collection Class VB.Net 2015

I Have the Following classes.
The first one is an Order Class and the Second one is a Collection of Orders.

I declare an Instance of this Collection Class.
Dim orderCollection = New ProductionOrderCollection

That works Fine - But I need to Refresh the Collection to get Updated Data from the Database.

Is there a Way to Refresh the Current Instance of the Collection Class or do I have to Remove the Instance and Create a New one?

orderCollection = nothing
orderCollection = New ProductionOrderCollection

Does Removing the Instance and Creating a New Instance waste Memory?

Order Class

Public Class ProductionOrder
    Public Property SalesOrderID As Integer
    Public Property CustomerName As String
    Public Property DespatchMethod As String
End Class

Order Collection Class

Public Class ProductionOrderCollection

    Inherits List(Of ProductionOrder)

    Public Sub New()
        'Declare the Handled Exception Collection
        Dim handledException = CustomErrorCollection.GetCustomErrorCollection

        'Declare Data Reader
        Dim drd As DbDataReader

		'Get Data from Data DLL
		drd = ProductionData.Orders

		While drd.Read
			Dim order As New ProductionOrder
			order.SalesOrderID = drd.GetInt32(0)
			order.CustomerName = drd.GetString(1)
			order.DespatchMethod = drd.GetString(2)
			Me.Add(order)
		End While

    End Sub
End Class