I'm trying to change the defined name string constant using VBA. Is it
possible? Here is my code:

Sub ChangeNameString()

Dim Next_String As String

' this works ok, defined name shows "First_String" (with quotes) (not a
variable)
ActiveWorkbook.Names.Add Name:="MyString", _
RefersToR1C1:="=""First_String"""

Next_String = "Second_String"

' doesn't work when attempting to change name with Next_String varible
(no quotes)
ActiveWorkbook.Names.Add Name:="MyString", _
RefersToR1C1:="=" & Next_String

End Sub

I've tried several variations but nothing works. Any ideas?