You can change the app icon to one you like from App Icon on the Other screen.
In rare cases, the new app icon is not applied correctly.
In that case, turn off your device, restart it, and then try changing the app icon again.
This resolves the issue.
This is an iOS issue, and restarting the device usually fixes it.
If the icon still does not change after restarting your device, please contact us from the button in the upper right of the help screen.
Thank you.