"Hello there! I see you were trying to reach me! What a wonderful idea! Sadly, the great Papyrus is unavailable to take your call at the moment, but that's okay! I'll probably call you back in about a minute, so go ahead and state your name and business!"
((OOC note: Papyrus nearly always answers on the first ring, so you can also go ahead and play it like that happened if you like.))