Hey @EricaAlfaro ,
Generally speaking, there are two types of webhooks - admin managed, and app managed. Admin managed webhooks can be infinitely adjusted through the admin notifications configuration screen without too much fuss, however app managed webhooks (which I assume we are talking about here) are a bit more tricky.
App managed webhooks are scoped to the app that was used to create them. That is to say, these webhooks can only be adjusted or managed by the app from which they originated. Because of this, to modify the existing webhook, you would need to process the request through the app that your developer used to create it initially. This may be difficult if you are no longer in a working relationship with that developer, or don't have access to their app code.
If you do have access to the app and need assistance, you could solicit the help of another developer (such as a Shopify Expert) to help build and send the necessary API calls through the app to modify the webhook. If this is not an option (such as having no access to the app code) then you'll need to consider rebuilding that app integration from the ground up.
I hope that helps!
Best,
