How to get SQL Server filetable path locator for subfolder by its literal path

I have a filetable which have several subtables. For example FileTable ->subtable1 ->->subtable1.1 ->->subtable1.2 ->subtable2 ->subtable3 etc How to get SQL Server path_locator for subtable given by something like '/subtable1/subtable1.1' ? I need it to move files from root to subfolder. I tried this, but its does not work declare @parent hierarchyid; set @parent = GetPathLocator('folder2/folder2.1') update physical_files set path_locator = @parent.GetDescendant(NULL, NULL) where stream_id = '494D5C8B-AC22-E411-A464-00259060BBB9'; SQL Server 2012 reports: > Msg 33423, level 16, state 1 > Invalid FileTable path name or format.