Update one of 2 duplicates in an sql server database table

Question

I have got a table that got a column with duplicate values. I would like to update one of a 2 duplicate values so for example row1 = tom and row2 = tom

Answer 1

Assume Table1, containing the following information:

Column1      
========  
tom        
john   
jack    
tom     
james
jane 

Notice that the first and fourth rows are identical. Here's the UPDATE command to change the name in only one of them.

UPDATE Table1 AS t1
   SET Column1 = 'jennifer'
 WHERE rrn(t1) =
       (SELECT MAX(rrn(t2))
          FROM Table1 AS t2
         WHERE Column1 = 'tom')

And the result would be

Column1      
========  
tom        
john   
jack    
jennifer
james
jane 

with RRN function you can update the last occurance of duplicate record