Board Thread:General Discussion/@comment-33178802-20180212045053/@comment-27136653-20180317221333

Galleigo wrote: Tsskyx wrote: The call is never picked up, Sans leaves a message. ...unless you get certain achievements. See the second part of this flowchart .

sans said: well, just calling to ask. ...appears if you have gotten certain special achievements (e.g. never took off bandage). This text indicates Frisk picked up the call. One can call a person without that person picking the call up. It's called voicemail. And since there doesn't appear to be a conversation between Sans and Frisk going on, nor there are any other indicators that would suggest the call has been picked up, I think it's safe to conclude it wasn't picked up.