Follow these instructions to change credentials.
When you have to change your Avans password, you have to remove the Eduroam profile and reinstall it using the above steps, providing the new password.
To delete the Eduroam Profile go to System Preferences and select Profiles:
Delete the Eduroam Profile using the "-" at the bottom left:
Press "remove" to remove the Eduroam Profile.
Now you will have to follow these instructions to re-install eduroam.