title: Replace column with another column
body: <p>I would like to replace the value of column Name.x with value from Name.y with condition if it is not NA (empty rows)</p>
  
  <pre><code>Name.x  Name.y
  US      NA
  Germany NA
  Germany France
  Canada  NA
  Italy     Morocco
  Austria Belgium
  </code></pre>
  
  <p>Result:</p>
  
  <pre><code>Name.x
  US
  Germany
  France
  Canada
  Morocco
  Belgium
  </code></pre>