[O] exit code editing buffer without installing the changes

[Not To Miss]

Hi org-mode users,

I know in a source code block, C-c ' will launch a buffer to edit the
source code and C-c ' again will install the buffer back to the code block.
Sometimes I just want to abort all the changes, so I am wondering: Is there
anyway to exit the buffer without installing the changes   and return to
the org file without any modification?

Thanks,
Zech