Call 911, then...
You or someone nearby should contact 911 asap.
If it appears they are chocking, then their mouth should be cleared of any obstruction or vomit.; then they would need the heimlich maneuver (http://www.Youtube.Com/watch?V=kjdpr05zmb4) they may need the “rescue breathing.” component classically taught with cpr. (http://www.Youtube.Com/watch?V=7wq5mup29jq) these recommendations are for adults only.