update using ROWID

How I can update record using ROWID???
Please give me an example using EMP table.

Thanks

update emp
set lname='Smith'
where rowid='aaaaaaaa.bbbbbbbb.cccccccccccc.ddddddd';
/* if v8 */

update emp
set lname='Jones'
where rowid='hhhhh.xx.cccccccc'

/* if V7 */

Yeh! it works, Thanks for your quick response.