title: changing a worksheet name
body: <p>On my named active EXCEL sheet I have put a string with fewer than 32 characters in let's say cell <code>A1</code>. </p>
  
  <p>I want to use the string in <code>A1</code> to rename the sheet. I have used VBA in the past but not for some time. </p>
  
  <p>I would be pleased if someone could suggest a macro that would do this when the cell A1 is clicked.  Are there any characters that cannot be in A1 (I want ~ and underscore)?</p>