How do I handle exceptions?

[koichirose]

If a user denies access to his/her Facebook account, I need a way to display an error and redirect to another page.

I understand that hauth/endpoint executes the following command:

require_once APPPATH.'/third_party/hybridauth/index.php';

I don't want to edit third party files, so how am I supposed to handle that exception?
Here it is:
( ! ) Fatal error: Uncaught exception 'Exception' with message 'Authentification failed! The user denied your request.' in /path/to/application/third_party/hybridauth/Hybrid/Auth.php on line 153

Thank you!