perform the Heimlich maneuver- place your fist slightly above their navel, take your other hand and place it on top of your other hand, press inward and upward in a "J" shape
if the casualty is pregnant or obese than use a chest thrust:
place your arms around the casualty under their armpits
make a fist with one hand and cover with your other hand
place both hands against the casualty's breastbone and pull inward
repeat either method until the airway is cleared

If the person becomes unconscious before the airway is clear, place them on the ground and send for medical help. Give the Heimlich by positioning the heel of a hand slightly above the navel and give several in-and-upward thrusts. Check the mouth for obstructions with a hook-shaped finger. Continue with thrusts and finger sweeps until medical help arrives or the obstruction is removed.

Note: please attend a first aid class for the proper method of giving chest thrusts to children under the age of 8.