WotLK Faction Change - Shadowmourne SFS Quest

[Nyrex]

If a toon is on SFS quest 35/50 and i decide to faction change it , what is happening with the quest ?

[Blind]

Questitems stay in your inventory even if you abandon and retake the quest.

I'd always finish the quest first before I change faction though - 15 shards shouldn't take terribly long to gather.