title: Neo4J - Conditionally setting value in merge
body: <p>In Neo4J I am creating nodes using "merge" for example -</p>
  
  <pre><code>MERGE (p: Person {id: 'testId1234' }) RETURN p
  </code></pre>
  
  <p>Now if understand this correctly a Node P will be created if one doesn't exist with id 'testId1234'. Now I want to set a property  <code>eligible_for_vote</code> only if the person's age was above 18, how can I do that?</p>
  
  <p>When I am inserting a node in the graph I do have access to their age. But I don't know how can I use <code>SET</code> conditionally along with <code>MERGE</code></p>
  
  <p>In short, I am trying to do something like this -</p>
  
  <pre><code>MERGE (p: Person {id: 'testId1234'})
  SET 
  if age &gt;= 18
    p.eligible_for_vote = true
  end
  p.age = 18
  RETURN p
  </code></pre>
  
  <p>any suggestions?</p>