Turn the lid counter-clockwise (left) to remove it.

Turn the cartidge cap clockwise (right) to remove it.

Remove the cartridge and replace it with a new one.

Begin by taking apart the pen to expose the refill. The process for this step can be found above.

Cut a strip of tape: Cut a small strip of tape that is approximately ~15-18MM long. The tape should be thin enough to fit inside the pen casing without causing the refill to get stuck.

Wrap the tape around the top of the refill: Hold the tape at one end, and gently wrap it around the top of the refill where it meets the casing. 

Make sure to keep the tape tight and evenly aligned as you wrap it around. The goal is to create a small loop of tape that will fill the gap between the refill and the casing, preventing any movement.

Adjust the tape loop: Once the tape is wrapped around the top of the refill, ensure that the loop is the correct thickness by testing the fit inside the pen casing. 

If the loop is too thick, the refill may get stuck, so you may need to trim the tape or try a thinner tape. Conversely, if the loop is too thin and the refill still moves within the casing, add another layer of tape.

Reassemble the pen: Once the tape loop is the appropriate thickness, reinsert the refill into the pen casing. Make sure the tape loop stays in place as you reassemble the pen.

Test the pen: Give the pen a quick test to ensure that the tape loop has successfully remedied the movement of the refill inside the casing. 

The pen should write smoothly and without any issues.