Readonly File, Changable Buffer

[Artist]

Hi,
 I like to read a file in emacs buffer and don't want to make any
change to the file itself, but should not have any problem in changing
buffer contents.
Thus I like to dis-associate the buffer from the file.
ex.. I like to sort the data in buffer etc..
I looked at dissociated-press but doesn't make much sense.

Thanks,
artist