You can use the Hal brain editor to go to and change Hal responses using a search function. But you have to first select the section of the brain that you want to do a search.
The most common place user input and new Hal reponses is stored is within the sections that have the user name in it like outlaw_ UserSent. Also check the sharedUserSent. Both of those sections are within the autoLearningBrain section of the main database table displayed within the brain editor.