Not exactly. We can change an array of size 5 into the size of 10, but it will create a new array and save in the old variable. But it is not possible to extend an array from 5 to 10 keeping its previous 5 values.
Look the example below
#include<iostream>
using namespace std;
int main()
{
int *arr;
int size = 3;
arr = new int[size];
arr[0] = 0;
arr[1] = 1;
arr[2] = 2;
for (int i = 0; i < 3; i++)
cout << endl << arr[i];
size = 5;
arr = new int[size]; // New sized array
arr[3] = 3;
arr[4] = 4;
for (int i = 0; i < 5; i++) // Previous three value are lost
cout << endl << arr[i];
cout << "\n";
return 0;
}