Thanks Eckhardt. I mean to migrate a sub-directory on repository server A to another sub-dir on repo server B. Not a "working copy" migration.
Wait: "working copies" are scrap space for editing, which you create when needed and throw away after use. "repositories" are databases that contain the files including their history. This just to get the terminology right, > ... and thanks Ryan, I will call our svn admin to apply the migrate method.