Hi RealAlan,
Thanks for contacting Apple Support Communities!
We understand that you're unable to adjust the time in your Pill Reminder app.
Since this app isn't developed by Apple, we'd suggest that you contact the app developer directly to help you to adjust the time within their app. If you need help to locate their contact details, you can reference this article for instructions: How to contact an app developer - Apple Support
You can also use the Reminders app which is part of the iOS as well if you'd like. This is a handy resource which will show you how to set up reminders and keep them updated across your devices: Use Reminders on your iPhone, iPad, or iPod touch - Apple Support
Create a reminder
1. Open the Reminders app.
2. Tap + New Reminder, then type your reminder.

You can also add reminders to your most important to-do lists from the Reminders widget on your Home Screen.
We hope this helps.
Cheers!