It can be done by replacing the original antenna and cable with a uFL/IPx to RP-SMA adaptor. It is an easy hardware mod, but it may void your warranty. After this you can install any 2.4GHz RP-SMA antenna including a patch type for longer but directional range.
Haynboy8.......something for you to consider before using any adapters, each adapter will reduce 1db, so two connectors will bring the antenna down to 3db
IMHO, Whyyy's suggestion to change out the connectors is a better work around
It truly gives 3dB boost over original 2dB antenna - confirmed with RSSI feature of FrSky telemetry. Even though it is longer then stock antenna, still fits my Turnigy 9x styrofoam box, without removing antenna.