Hi Jonathon,
Thank you for contacting Syncfusion support.
Currently we don't have the support to edit existing Pdf document and we have already added the feature request for "Need to add support to edit the existing document text" to our database.
The feature implementation would also greatly depend on the factors such as product design, code compatibility and complexity. This feature will be included in one of our future releases. We request you to visit our website periodically for feature updates.
With Regards,
Sasi Kumar