Tap the message actions icon on the message header to access action options for the message.
Tap to reply or and choose Reply all or Forward.
Replying to or forwarding messages without changing the subject adds your reply to the current conversation.
Changing the subject starts a new conversation.
The message will open in a new screen where you can add or remove addresses, edit the subject, and add or remove text or attachments.
You can add one or more people to an ongoing conversation by replying to all and then adding the new person’s address(es) to the reply.
Note that the conversation text and previous messages are also included in your reply (or forward).
Tap Send at the top of the screen to send your message.