You can use the Invitation editor to preview the changes made to your forms.
View your invitation in the invitation editor. There are two ways to open the invitation editor:
Go to your venue homepage, click 'Edit Group', and click on your invitation of choice under 'Related Invitations'.
Go to https://openreview.net/invitation/edit?id=Your/Venue/Id/-/Invitation
Edit the Reply Parameters field. Enter and remove fields in valid JSON as you choose. Do not hit 'Save Invitation'.
View your changes in the 'Preview' tab.
Once you are happy with your JSON, use the venue request form to make your desired changes to the form. You can copy the JSON of new fields into the 'Additional ___Options' field, and remove fields using the 'Remove___ Options' field.