Hi, thank you for contacting JustAnswer.com. My name is Russell. I will do my best to provide the right answer to your question.
At first glance, I suspected that your question might relate to a function, not of your phone, but rather of your phone station's system box, that is to say the box (usually in an equipment closet or back room) that runs your local or office phone system.
On some research on this type of phone, I turned up indications that the Auto Attendant feature is probably on the phone system box, but that you may be able to change its settings (or rather, your 'status' as to the Auto Attendant.) This changing of status is done by pressing the Auto-Attendant function key.
Which key on your phone is the Auto-Attendant key? that's hard to say. The indication I turned up seems to say
whatever that means precisely.
It might be tedious, but if your phone is programmed with (or intrinsically has) an Auto-Attendant key, then you should be able to find out which one it is, by pressing the HELP key followed by another key... which should make the phone state what function is assigned to that key.