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

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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

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