In all the years we have gone to WDW, I can count on one hand how many times i have heard an overhead page for anyone. WDW has a sophisticated way of getting ahold of CMs, but I don't think there would be any way for her to have a Cm get ahold of you.
If you are staying at a WDW resort, you will have voicemail on your room phone so she can leave a message for you there. As far as I know, you don't need to be in your room to pick up messages.
If she is not able to reach youdirectly on your cell phone, she can leave a voice mail for you on the cell phone (assuming you have voice mail). If your phone is not on or not reachable when she calls you, you will get an alert that tells you there is a message as soon as your phone is available.