title: SQL Server: Alter a clustered primary index to an non-clustered
body: <p>How do I alter a primary clustered index to become a non-clustured index. (Being a "secondary" table I want to use the clustured index for the foreign key column of the "header" table.)</p>
  
  <p>This doen't work for me (error seems reasonable :)</p>
  
  <pre><code>DROP INDEX ClientUsers.PK_ClientUsers
  CREATE UNIQUE CLUSTERED INDEX IDX_ClientUsers_Id ON ClientUsers(Id)
  
  Msg 3723, Level 16, State 4, Line 7
  An explicit DROP INDEX is not allowed on index 'ClientUsers.PK_ClientUsers'. 
  It is being used for PRIMARY KEY constraint enforcement.
  </code></pre>