Appending to go lang slice using reflection

For some reason, it appears that adding new element to slice using reflection doesn't update slice itself. This is the code to demonstrate:

package main

import (
    "fmt"
    "reflect"
)

func appendToSlice(arrPtr interface{}) {
    valuePtr := reflect.ValueOf(arrPtr)
    value := valuePtr.Elem()
    value = reflect.Append(value, reflect.ValueOf(55))

    fmt.Println(value.Len()) // prints 1
}

func main() {
    arr := []int{}
    appendToSlice(&arr)
    fmt.Println(len(arr)) // prints 0
}

Playground link : http://ift.tt/2lYUgJs

Is there something I'm missing here?