VBA Copy a file as a different file extension - excel

Question

I am trying to build a data formatter where the user selects a file of type .xlsx and then I format it and save it as type .csv. I am needing to convert the xlsx file to a csv before I can format it. To do this, I couldn't find anything apart from opening the file, copying the used range to a worksheet on the original file, saving that worksheet as csv and then referencing that file. Despite a lack of elegance, this would work fine for the use case. However, I cannot seem to get the copying of the worksheet to be formatted down.
Here's what I'm trying for copying:
Dim active As Worksheet
Set active = ActiveSheet
With Workbooks.Open(myFile)
ActiveSheet.UsedRange.Copy
active.Paste
.Close SaveChanges:=False
End With
This, in theory, should copy the data from the file being opened to the already opened file, but it doesn't.

Answer 1

This works great for me:
As a sub:
Sub ConvertToCSV()
Dim MyFile As String
Dim WBtmp As Workbook
Application.EnableEvents = False
Application.ScreenUpdating = False
Application.Calculation = xlCalculationManual
MyFile = "C:\Users\cameron\Documents\IDs.xlsx"
Set WBtmp = Workbooks.Open(MyFile)
With WBtmp
.SaveAs Replace(MyFile, ".xlsx", ""), xlCSV
.Close
End With
Application.EnableEvents = True
Application.ScreenUpdating = True
Application.Calculation = xlCalculationAutomatic
End Sub
Or as a function
Sub TestFunc()
fConvertToCSV "C:\Users\cameron\Documents\IDs.xlsx"
End Sub
Function fConvertToCSV(MyFile As String)
Dim WBtmp As Workbook
Application.EnableEvents = False
Application.ScreenUpdating = False
Application.Calculation = xlCalculationManual
Set WBtmp = Workbooks.Open(MyFile)
With WBtmp
.SaveAs Replace(MyFile, ".xlsx", ""), xlCSV
.Close
End With
Application.EnableEvents = True
Application.ScreenUpdating = True
Application.Calculation = xlCalculationAutomatic
End Function