This quest is not available in game.
Bring your Violet Signet to Archmage Leryda at Deadwind Pass after obtaining Exalted reputation with the Violet Eye.
Your services have gone above and beyond what is expected of you, <name>. You are but a step away from achieving the highest honor available to non-citizens of Dalaran.
Continue to prove your loyalty to us and I will empower your signet to its full capacity.