The earliest
source I could find on Soothsaying for Dummies is from april 2007, which is 3 months after TBC released.
However, in the
1.10 patchnotes under Professions:
Blizzard Entertainment wrote:Players that unlearn Engineering or Leatherworking may now respecialize if they decide to relearn the professions.
The
Wowwiki engineering guide sais:
Since patch 1.10, it has been possible to switch engineering specializations. It is, however, painful. To switch from gnomish to goblin or vice versa
- Press K to bring up your skills tab, click on engineering, and then click an icon that looks like a circle with a slash through it to un-learn engineering entirely.
- Visit an engineering trainer and start all over again at level 1
- Level your skill to 225
- Visit Narain Soothfancy's house North of Steamwheedle Port in Tanaris, and read Soothsaying for Dummies.
- Select a new Engineering Specialization (or your old one if you had a change of heart)
Not sure if the Wowwiki information is entirely correct, but at least we know you can change specs if you want to.