The easiest way to reset push notifications on iOS is to simply reinstall the app. Here is how to proceed:

1. Go to your Home Screen, long-press on the app icon (A), and tap Delete Bookmark (B).

2. Open Safari (C) and navigate to the website from where you installed the app.

3. Open the Share Sheet (D) from the menu bar.

4. Scroll and tap Add To Home Screen (E), and then Add (F).

4. Launch the newly installed app (G) from your home screen. Within a few seconds, you should be prompted to allow notifications again!