There is a lip on the inside that holds pretty well. Just pinch the hose hard downward and start working off the top bit....dont worry about breaking it, its pretty durable. (its the wires inside that are not) Sometimes carefully sliding a flatblade screwdriver inbetween can help start it.
I hope you are reffering to the wiring harness connected to the outside as the inner wires shouldnt be touched. As for getting the harness off,there is a clip that needs to be pryed away. There is ALWAYS a clip of some sort holding a harness together.....its just a matter of figuring out what style.
You must manually reset the check engine light by either disconnecting your battery or removing the engine management fuse located on the side of the dash on the driver side. (or you can do it with an OBDII scanner) Did you get the code pulled originally and thats what lead you to the MAF?