Syncing file with reference to another one

[Hai Zaar]

I have the following situation: file2 on remote host and file1 on
localhost. file1 and file2 are mostly the same. Simply running
  rsync remotehost:file2 file2
will actually transfer the entire file. But I would like to use the
factt that I have local file1 that is mostly similar to file2. I.e.
how can I make rsync to use file1 as a reference while transferring
file2? (cp file1 file2 locally and then using --inplace switch to
rsync sound like and idea, but look awkward for me. Anything better?)

Thank you for your help.
--
Zaar