How to re-trigger contacts in an API goal campaign sequence?

I have campaign set up using an API goal of Treatment Status, exam completed that takes contacts either through an email sequence or to a fulfillment listed based on whether or not they have an email. The end goal of the sequence is another API goal of appointment added.

I’m having an issue with contacts either cancelling their appointment or their email address being invalid and therefore, not completing the sequence.

Do I add another API goal of appointment deleted and then restart the email/fulfillment lists or should I add some sort of tag?

We use the DentmaBridge integration.

You can continue to use the tag goal approach as long as you are certain to drop the tag the moment the contact enters the first sequence.