If the issue persists after the previous step, the motor may have an internal issue and the affected motor(s) will need to be replaced.

Locate the problem motor(s) and desolder the three wires attached to the electronic speed controller (ESC) after removing the heat-shrink tubing.

Remove the four screws on the bottom of the motor affixing the motor to the arm of the drone so the motor can be removed (repeat this for any # of broken motors).

Note: if the carbon fiber on your arms has begun to delaminate, be careful while unscrewing the motor(s) here because you could get a carbon fiber splinter, and those hurt.