[support] can i hook a hook?

Hello, Having a terrible time finding anything about this, and all I can find on Drupal.org is the API for hooks, which doesn't really explain enough. My question is, if there is a contrib module with an implementation of: hook_block() such as: nodeasblock_block() How can I change the values inside of this function, without changing the function directly? can I write something in template.php to catch the nodeasblock_block hook and then change the values in it? Or do I need to change the nodeasblock module directly? perhaps adding the feature as a full blown check box addition or just hack it?? Thanks for any help you can provide me! kindly, Sebastian.