VBA – Delete All Named Ranges
Delete all Named Ranges From a Workbook
To delete all Named Ranges in a Workbook, you can use the following code:
Sub DeleteNamedRanges()
Dim MyName As Name
For Each MyName In Names
ActiveWorkbook.Names(MyName.Name).Delete
Next
End Sub
For determining whether a name exists, adding a named range, and a few other examples, Chip Pearson has a nice tutorial on working with Named Ranges.