# Replying to a Message

<!-- Version variant: core_9; default: [/nservicebus/messaging/reply-to-a-message.md](/nservicebus/messaging/reply-to-a-message.md) -->


The simplest way to reply to a message is using the `Reply` method:

<!-- snippet: ReplyingMessageHandler -->

```cs
public Task Handle(RequestDataMessage message, IMessageHandlerContext context)
{
    // Create a response message:
    var response = new DataResponseMessage
    {
        DataId = message.DataId,
        String = message.String
    };

    // Reply sends a new message to the return address on the message being handled.
    return context.Reply(response);
}
```

<!-- endsnippet -->

Only use a reply when implementing the Request-Response pattern (also called the Full Duplex pattern). In this pattern, the originator of the message should expect a response message and have a handler for it. For examples and more information, see the [Full Duplex Sample](/samples/fullduplex/index.md) and the article [Callbacks](/nservicebus/messaging/callbacks.md).

When using the Publish-Subscribe pattern, an endpoint handling an event shouldn't use `Reply`. This is because the publisher might not expect a reply and has no message handler for the replied message.

The reply address is controlled by the sender of the message being replied to. See [how to influence the reply behavior when sending messages](send-a-message.md#influencing-the-reply-behavior).

## Influencing the reply behavior

A sender of a reply can influence how the requester will behave when continuing the conversation (replying to a reply). It can request a reply to go to itself (not any other instance of the same endpoint)

<!-- snippet: BasicReplyReplyToThisInstance -->

```cs
var options = new ReplyOptions();
options.RouteReplyToThisInstance();
var myMessage = new MyMessage();
await context.Reply(myMessage, options);
```

<!-- endsnippet -->

or explicitly to any instance of the endpoint (which overrides the *public reply address* setting)

<!-- snippet: BasicReplyReplyToAnyInstance -->

```cs
var options = new ReplyOptions();
options.RouteReplyToAnyInstance();
var myMessage = new MyMessage();
await context.Reply(myMessage, options);
```

<!-- endsnippet -->

It can also request the reply to be routed to a specified transport address.

<!-- snippet: BasicReplyReplyToDestination -->

```cs
var options = new ReplyOptions();
options.RouteReplyTo("MyDestination");
var myMessage = new MyMessage();
await context.Reply(myMessage, options);
```

<!-- endsnippet -->

> [!NOTE]
> Replies participate in the handler transaction and are not sent if the message rolls back. If the code requires a response, whether or not message processing succeeds, use [immediate dispatch](/nservicebus/messaging/send-a-message.md#dispatching-a-message-immediately) on the reply options. Make sure exceptions are rethrown to rollback any transactions and use a [custom recoverability policy](/nservicebus/recoverability/custom-recoverability-policy.md) to not retry non-transient errors.