How to properly deal with dynamically allocated memory

main.c

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

int main(int argc, char* argv[]) {
    int* arr = calloc(256, sizeof(int));
    if (arr == NULL) {
        return 1;
    }
    
    memset(arr, 0, sizeof(int) * 256);
    arr = realloc(arr, 64 * sizeof(int));
    
    free(arr);
    return 0;
}