The Cavalry Charger feat enables the use of three tactical maneuvers.

Unhorse: To use this maneuver, you must be mounted and charge a mounted foe. If your charge attack hits, you may make a free bull rush attempt. If the bull rush attempt succeeds, you move your foe normally, but his mount remains where it was.

Leaping Charge: To use this maneuver, you must be mounted and charge a foe. Against a foe of at least one size category smaller than your mount, make a DC 15 Ride check at the conclusion of the move portion of the charge action. Against a foe of equal or greater size category than your mount, make a DC 20 Ride check. If you succeed, you deal additional bonus damage equal to number subtracted from your attack rolls from use of Power Attack. If you fail this Ride check, you miss your target (no attack roll) and if you fail this Ride check by 5 or more, you miss your target and fall off your mount, landing in a square adjacent to the mount's space. 

Fell Trample: You can make mounted overrun attempts against more than one foe, resolving each attempt individually. Your mount gets a hoof attack against each foe you successfully overrun.