Reply to a message in a buffer

[Saptarshi]

Hello,
I don't use GNUS but I do use GMail. I sometimes copy the message from
a gmail (by selecting the original source sans headers from GMail)
paste it in an emacs buffer and turn on message-mode. However, this
treats the buffer as the message, whereas I would like to reply to the
message in the buffer.

Is there a message-mode function that will reply(create a new buffer)
to a buffer that contains an email message?
Thanks and regards
Saptarshi