You can add or remove your out of office auto-reply by going to bluehost.com, clicking Login in the top right, then selecting Webmail Login, and logging in with your email username and password:
Then click the gear icon at the bottom that says "auto-responders".
If you happened to set the Autoload feature of your preferred webmail software to zero seconds and now it won’t let you change to a different webmail application, you can disable webmail from autoloading, whether you chose Horde Webmail, Roundcube or Squirrel Mail:
After it loads you into the webmail application, simply click the back button on your browser and then click “Disable AutoLoad.”
This is important as the "auto responders" icon is at the bottom of the initial login page where you can choose Horde, Roundcube, or Squirrel Mail. If you've configured it to AutoLoad, it will skip this page and send you directly to your webmail application.