@NatM DocuSign fields are color coded per Recipient.  If you have an envelope with two Recipients, Recipient 1 fields will typically be yellow and Recipient 2 a light blue color.  It is possible all fields were added under the same Recipient or an incorrect Recipient.   When correcting and goin gin to the Next screen where DocuSign fields can be added, check the top left corner to make sure it is on the correct Recipient.   If you still cannot add the fields then the best option is to void and create a new envelope. I have run across situations when an attachment has been added to the envelope that will then no longer allow any changes in the correction outside of adding a new Recipient, perhaps you could try adding a Recipient as “Needs to Sign” adding fields for the new Recipient, and then removing the second Recipient, this swapping the new for the one you are removing.

Thank you David. I definitely have recipients added as different fields. I’m just changing one signatory (initial signatory hasn’t signed) so I should be able to Correct, Add a signatory, change the old signatorys role to Receives a Copy then Add Field as I’ve done in the past. The option comes up but it doesn’t let me Add Field. Nothing has been attached to the envelope since I sent it.

I was trying to avoid voiding and resending. 

SOLVED: What I did was replace the initial signatory details with the updated details then re-added the initial signatory as a NEW “Receives a Copy” recipient - that seems to solve it.