How to modify a pointer value in C++

#include <iostream>
#include <string>
using namespace std;
int main() {
  // creating a variable
  string name = "Pizza";
  // creating a pointer to the variable
  string* ptr = &name;
  // printing the value of the variable
  cout << "This is the value of the variable: " << name << "\n";
  // obtaining and printing the memory adress of the variable
  cout <<"This is the memory adress of the variable: " << &name << "\n";
  // obtaining and printing the value of the variable using * operator
  cout <<"This is also the value of the variable: "<< *ptr << "\n";
  
  // Changing the value of the pointer
  *ptr = "David";
  
  // obtaining and printing the new value of the pointer
  cout << "This is the new pointer value: "<< *ptr << "\n";
  
  // printing the new value of the name variable
  cout << "This is the modified name of the variable: "<< name << "\n";
  return 0;
}