how do i dynamically change the structs json tag

[lm2333]

I'm referencing a struct of third-party library, eg look like:

type User struct {
    ID   int64  `json:"id"`
    Name string `json:"first"` // want to change this to `json:"name"`
    tag  string `json:"-"`
    Another
}

type Another struct {
    Address string `json:"address"`
}

I now have the following:

package main

import (
    "encoding/json"
    "fmt"
    "os"
)
type MyUser User

func main() {
        anoth := Another{"123 Jennings Street"}
    _ = json.NewEncoder(os.Stdout).Encode(
        &MyUser {1, "Ken Jennings", "name",
             anoth},
    )
}

I am trying to json encode the struct but before I do I need to change the json key...eg the final json should look like:

{"id": 1, "name": "Ken Jennings", "address": "123 Jennings Street"}

how can i do it