Hi there rrroven,
Thank you for using Apple Support Communities!
It sounds as though you’re looking to remove previous saved data from an app. You’re in the right place, we’d be glad to assist in seeking a solution.
Depending on the app, apps can save data locally to your iPhone or they can use Game Center to keep your progress and game saves the same across your devices. Below is a resource that can help:
Access your Apple Arcade gameplay data on all of your devices
This resource provides great information on how games can use iCloud or Game Center to keep progress up to date. The information in this resource also applies to games that are not in Apple Arcade. If you need further assistance after checking out that resource, we’d advise reaching out to the app developer directly. Below is a resource that can help with contacting the app developer:
How to contact an app developer
We hope this helps,
Cheers!