Do you call the room to "At Ease" when a senior NCO walks in and you are the only soldier in there?

I was in my office today and when my 1sg walked in for the 2nd time today. I stood up and went to the position of AT EASE. She then chewed me out because I din't call "AT EASE". I told her that you don't call it because she wasn't leaving for the day and that I was the only soldier in here. I didn't think I was supposed to call myself to the position of "AT EASE". I tried to find it online and asking others but we cant find it. Can somebody please help me with this.