title: How to allow duplicate-recipients for a given DocuSign Envelope?
body: <p>We need our signers to be able to change signing method, i.e. to change from embedded signing to e-mail signing and vice versa.  The difference is marked, essentially, by the presence/absence of the recipients.signers.clientUserId attribute, and, to my knowledge, the REST API does not accommodate this as a change <em>per se</em>.</p>
  
  <p>So, in order to change the signing method, I had to do an add/drop.  (Note that doing the drop first could disrupt the routing order, e.g. if I drop the remaining user in routing order 1, the envelope will immediately move on to routing order 2... so the add must occur first.)  I maintain a suffix to distinguish between instances of the signer during this type of change.  A recipient may start out with recipientId 100; upon changing signing method he becomes 101, and so on.  Tabs have to be added separately to the "new" user, 101, and then the "old" user, 100, is dropped.</p>
  
  <p>This method has been working for several months.  Of late, however, we are receiving a duplicate-recipient error on the add.</p>
  
  <p>On the other hand, we used to get an error if starting an envelope with duplicate signers, and now we don't.</p>
  
  <p>Has anyone else experienced a change in the duplicate-recipient error?</p>