I live in Iowa and I am talking to a person in Idaho (or anyone in a different state), and the person on the other end experiences a sudden illness and needs EMS, what is the best way to get services out to the person you are chatting with (assuming you know their address)?
Answer for the US and Canada:
Call 911 and explain the situation. They will be able to either forward your call or give you a number to call faster than you can find it on your own. Dispatch centers contact each other all the time so they know in advance how to do so.
If that doesn't work for some reason, grab google and type in "[Somewhere] Idaho Police Department" and call them directly. Next attempt: Idaho State Police.
Rest of the world:
Call the local emergency number and do the same. For example, in most of Europe that would be 112.
Source: Me, 15 years of experience in EMS. Can't find a good source to reference.