Change Property name when Serializing

Hi Guys,

I'm trying to change property name when Serializing from Reference to ref but doesn't seems to be working, it still creates a JSON file with Reference property?
public class Authority {     [JsonProperty(PropertyName = "ref")]     public string Reference { get; set; }     public string name { get; set; } }
MyCalss.Authority.Reference="value"
but still shows:
"authority": { "Reference": "value",Thanks