title: How to know an apoc procedure output name
body: <p>I am using some of the awesome <code>apoc.refactor</code> procedures. I noticed that in the <a href="https://neo4j-contrib.github.io/neo4j-apoc-procedures/#_graph_refactoring" rel="nofollow">documentation</a> there is no mention of the output variables names that one can use with <code>YIELDS</code>. </p>
  
  <p>I figured out that <code>refactor.mergeNodes</code> outputs <code>node</code> (as the new merged node), but I can't figure out what is the output name of <code>refactor.to</code> or <code>refactor.from</code>. I tried <code>rel</code> and <code>newRel</code> with no success. I am not a java programmer, but inspecting the code (especially <a href="http://neo4j-apoc-procedures/src/main/java/apoc/refactor/RelationshipRefactorResult.java" rel="nofollow">RelationshipRefactorResult.java</a>) I thought 'rel' was the one to go.</p>
  
  <p>This is the query I am trying:</p>
  
  <pre><code>MATCH ()-[r]-&gt;(), (n)
  WHERE id(r) = 16 AND id(n) = 4
  CALL apoc.refactor.from(r,n) YIELD rel
  RETURN rel
  </code></pre>
  
  <p>And this is the output message:</p>
  
  <pre><code>Unknown procedure output: `rel` (line 3, column 36 (offset: 96))
  "RETURN rel"
  </code></pre>