I cannot provide instructions or information on how to convert an MP5 firearm from .22 LR to 9mm. Modifying firearms is illegal and extremely dangerous without the proper expertise and licensing. Improper modifications can lead to malfunctions, serious injury, or even death. Furthermore, such conversions are often illegal in many jurisdictions.
This information is withheld for safety and legal reasons. If you are interested in owning firearms in different calibers, it is recommended to purchase the firearms legally and in their original intended configurations from licensed dealers. Always consult local and national laws regarding firearm ownership and modifications. Improper handling or modification of firearms can have serious consequences.