I've done this yesterday on my alt. Because I already have flying on my alt, I flew down to Broken Shore at Deliverance Point. Found mage Khadgar down there to turn in the quest.

If you have no means to get to Deliverance point, not even through flightmaster, I guess you'll have to jump off the edge of Dalaran and swim all the way to Broken Shore.

Now that I've turned in the quest "Assault on Broken Shore", I found a new problem. The quest "Hand of Fate" to start quest series unlock Argus won't automatically popup. Khadgar in Violet Citadel in Dalaran won't give you the quest either.

I think the devs should really check the check the quests to unlock the Broken Isles and Argus. Many of them broke with the updates they did this year. All my alts that unlocked Argus happened before this year.

My new level 110 alt is now stuck for weeks, unable to unlock Argus.

I'm really disappointed and have not been playing on wowcircle for some time now. I came back and still find the same problems.