diff --git a/src/Sinch/Voice/Callouts/Callout/DestinationType.cs b/src/Sinch/Voice/Callouts/Callout/DestinationType.cs
index 434923d..4fe6ad2 100644
--- a/src/Sinch/Voice/Callouts/Callout/DestinationType.cs
+++ b/src/Sinch/Voice/Callouts/Callout/DestinationType.cs
@@ -12,6 +12,6 @@ public record DestinationType(string Value) : EnumRecord(Value)
     {
         public static readonly DestinationType Number = new("number");
         public static readonly DestinationType Username = new("username");
-
+        public static readonly DestinationType Sip = new("sip");
     }
 }
diff --git a/src/Sinch/Voice/Common/Destination.cs b/src/Sinch/Voice/Common/Destination.cs
index 7c91d9c..f25e7f7 100644
--- a/src/Sinch/Voice/Common/Destination.cs
+++ b/src/Sinch/Voice/Common/Destination.cs
@@ -54,9 +54,14 @@ public override string ToString()
     [JsonConverter(typeof(EnumRecordJsonConverter<DestinationType>))]
     public record DestinationType(string Value) : EnumRecord(Value)
     {
-
-        public static readonly DestinationType Number = new("Number");
-        public static readonly DestinationType Username = new("Username");
+        /// <summary>
+        ///     Destination ptsn
+        /// </summary>
+        public static readonly DestinationType Number = new("number");
+        /// <summary>
+        ///     Destination mxp
+        /// </summary>
+        public static readonly DestinationType Username = new("username");
         public static readonly DestinationType Sip = new("sip");
         public static readonly DestinationType Did = new("did");
     }
diff --git a/src/Sinch/Voice/Hooks/To.cs b/src/Sinch/Voice/Hooks/To.cs
index 0ac751c..368afc8 100644
--- a/src/Sinch/Voice/Hooks/To.cs
+++ b/src/Sinch/Voice/Hooks/To.cs
@@ -1,4 +1,5 @@
 using System.Text.Json.Serialization;
+using Sinch.Voice.Common;
 
 namespace Sinch.Voice.Hooks
 {
@@ -11,7 +12,7 @@ public class To
         ///     The type of the destination.
         /// </summary>
         [JsonPropertyName("type")]
-        public string? Type { get; set; }
+        public Destination? Type { get; set; }
 
         /// <summary>
         ///     The phone number, user name, or other identifier of the destination.