If you need to reset your username or password for an app, you'll typically need to follow the specific procedures provided by the app or platform itself. Here's a general guide on how to reset your app username or password:

1. Open the app: Launch the app on your device.

2. Locate the login screen: Look for the login or sign-in screen within the app.

3. Find the "Forgot password" or "Reset password" option: Most apps have a password recovery option. Look for a link or button that says "Forgot password" or "Reset password." It's usually located near the login fields.

4. Reset your password: Tap on the "Forgot password" or "Reset password" option. You may be asked to provide your email address or username associated with the account. Enter the required information and follow the instructions provided.

5. Check your email or follow the instructions: After submitting your email address or username, the app should send you an email with instructions on how to reset your password. Check your email inbox and follow the instructions provided. If you don't receive an email, make sure to check your spam or junk folder.

6. Set a new password: Once you've accessed the password reset link or instructions, you'll usually be prompted to create a new password. Choose a strong, unique password and enter it as instructed. Some apps may have specific

the app doesnt have a forgot/reset password options!

Are you mentioning the Wi-Fi credentials or login credentials for GUI portal?

If you mentioned to reset the Wi-Fi password on SBC app, please follow the instructions given below:

http://arris.force.com/consumers/articles/General_FAQs/SURFboard-Central-Changing-the-Wi-Fi-Name-Password 

I’m having the same issue, I need to reset the APP password in order to change my WiFi password. There is no password reset function.

There is no option to reset the login password on the surfboard central app. so only by resetting modem you can create new login credentials for the app. Uninstall the app then reset the modem after modem reboots completely connect your device to the modem default WIFI network then install the app and login using new email id, password.  But after resetting the modem will go to default setup any custom settings will be removed so use the default network name and password to connect to your network.

http://arris.force.com/consumers/articles/General_FAQs/G34-G36-Factory-Reset