title: Remove EntityReference from CRM 2015 value
body: <p>I am doing a tool to synchronize some to data between CRM and another application.
  Now I have to remove the value from a EntityReference. I am trying in this way:</p>
  
  <pre><code>contact.ParentCustomerId = null;
  </code></pre>
  
  <p>But it does not work. That does not give me any error bur when I go to CRM via browser the field is till valorized.
  I have also tried in this way:</p>
  
  <pre><code>contact.ParentCustomerId = new EntityReference(Crm.Context.Account.EntityLogicalName, Guid.Empty);
  </code></pre>
  
  <p>but this give me a runtime error.</p>
  
  <p>How can I solve? Thank you</p>
  
  <p><strong>UPDATE :</strong> </p>
  
  <pre><code> Crm.Context.Contact contatto = ContattiTOA.Transform(c, account); //Inside the transform you can see that line of code I posted before..
  
   var entityToUpdate = this._context
                                  .ContactSet
                                  .Where(cont =&gt; cont.new_SIP_id == contatto.new_SIP_id || cont.Id == contatto.Id)
                                  .First();
  
          if (entityToUpdate.new_SynchronizewithSIP.HasValue &amp;&amp; entityToUpdate.new_SynchronizewithSIP.Value == true)
          {
              contatto.Id = entityToUpdate.Id;
              contatto.OwnerId = entityToUpdate.OwnerId;
              contatto.EntityState = EntityState.Changed;
  
              request = new UpdateRequest { Target = contatto };
          }
  
          requests.Requests.Add(request);
  
          ExecuteMultipleResponse responses = (ExecuteMultipleResponse)this._context.Execute(requests);
  
          foreach (var responseItem in responses.Responses)
          {
              if (responseItem.Fault != null)
              {
                  ... // I never fall in here
              }
          }
  </code></pre>