Changing filament in a 3D printer is a relatively simple process. First, you will have to unload the current filament from the 3D printer, which can be done by retracting it out of the extruder. Then you will have to load in your new filament and feed it through until it comes out of the hot end.  Finally, you will then need to make sure that the extruder is correctly calibrated with its new material.