title: Import data from excel sheet with new columns in CRM 2013 Online
body: <p>I previously imported data from an excel sheet into CRM that had around a dozen columns in it. At that time some of those columns were empty. Now that excel sheet has been updated to include values in those previously empty columns. 
  How do I import only those newly updated columns in excel sheet to update their respective CRM records? Is their a way of importing them without creating duplicates and anyway messing up the records in CRM?</p>