The "revert" command:

Usage: fossil revert ?-r REVISION? ?FILE ...?

Revert to the current repository version of FILE, or to
the version associated with baseline REVISION if the -r flag
appears.

If FILE was part of a rename operation, both the original file
and the renamed file are reverted.

Revert all files if no file name is provided.

If a file is reverted accidently, it can be restored using
the "fossil undo" command.

Options:
  -r REVISION    revert given FILE(s) back to given REVISION

See also: redo, undo, update