Unscrew the pen cap from the pen body, and unscrew the pen body from the plastic ink reservoir and nib mechanism.
Unscrew the ink reservoir from the nib and set the nib mechanism aside. You now have four sections: cap, pen body, nib mechanism and plastic reservoir.
Use the eyedropper to transfer ink into the ink reservoir. The ink should fill to between two-thirds to three-quarters of the reservoir.
Screw the plastic ink reservoir back together with the nib mechanism, and reconnect the pen body back onto the nib mechanism.
Hold the pen so that it is horizontal to the ground, and wrap a paper towel loosely around the nib to trap excess ink; then shake the pen gently several times to load the nib mechanism with ink. The nib mechanism will click (this is normal).
Test the ink flow on a piece of scrap paper. If the ink does not flow smoothly, rewrap the paper towel around the nib and shake the pen a few more times to start the ink flow.
Unscrew the pen cap from the pen body, and push the colored tab at the base of the pen body so that the nib and cartridge are released.
Remove the cartridge from the pen body and dispose of it.
Insert the new cartridge into the pen body until it is secure.
Hold the pen so that it is horizontal to the ground, and wrap a paper towel loosely around the nib to trap excess ink; then shake the pen gently several times to load the nib mechanism with ink. The nib mechanism will click (this is normal).
Test the ink flow on a piece of paper. If the ink does not flow smoothly, rewrap the paper towel around the nib and shake the pen a few more times to start the ink flow.