You can change the name of Lei Jianshi in the game by the following steps:

1. Find the plastic surgeon and enter his shop.

2. Select the Change Name option.

3. Enter the name you want to change.

4. Confirm the change and pay the required fees.

After completing the above steps, Lei Jianshi's name will be changed. It should be noted that if Kensley has a unique dialogue, even if it is changed by a plastic surgeon, it will remain.