After you have rested and recovered, Kan-E-Senna has an important request for you.
This quest is only available if you started the game in Gridania, you have completed the quest Renewing the Covenant, and have reached level 15.
Starting the Quest
Speak to Kan-E-Senna in the Lotus Stand, accessible by talking to the Silent Conjurer near the Conjurers' Guild aetheryte in Gridania, to start the quest. There will be a cutscene.
Speak with Miounne
Go back the way you came and leave the Lotus Stand, then go back to the main aetheryte of Gridania and go south to the Carline Canopy. Talk to Miounne. There will be a cutscene.
Speak with Lionnellais
Go down the stairs in the Carline Canopy to find Lionnellais. Talk to him, and say Yes to proceed to the landing area.
Board the Airship
Go outside through the door nearby and follow the path. Check on the gangplank, then say Yes to board the airship.
Speak with the Storm Honor Guard
Go down the path on the right and talk to the Arrivals Attendant. Say Yes to leave the landing area. Go forward and talk to the Storm Honor Guard.
Present Kan-E-Senna's Missive
Speak to Blanmhas, the Lift Attendant, and choose to go to Bulwark Hall. Turn left and follow the path out to the main aetheryte of Limsa Lominsa. Attune to it. It is recommended to attune to all the aetheryte crystals in Limsa Lominsa when you have the chance to do so.
Go back the way you came, to the quest location marked on the map and minimap. Talk to Zanthael and hand over the Letter to the Admiral, and there will be a cutscene.
Speak with L'nophlo
Your next destination is the Airship Landing in Limsa Lominsa. The door to the lift is on the other side of this room. Go there and talk to Grehfarr, and ride the lift to the Airship Landing. Once there, talk to L'nophlo and say Yes to proceed to the landing area.
Board the Airship in Limsa Lominsa
Follow the path to the gangplank. Check on it and say Yes to board the airship.
Speak with the Flame Honor Guard
Go forward and speak to the Arrivals Attendant, and say Yes to leave the landing area. Step forward and talk to the Flame Honor Guard.
Present Kan-E-Senna's Missive in Ul'dah
After speaking with the Flame Honor Guard, turn left and go down the ramp, and talk to Nanahomi. Take the lift to the Hustings Strip.
Follow the path and look for a path to the right. Follow it and you will find an aetheryte crystal. Attune to it, then make your way around the circle to go to the green check mark. Talk to Bartholomew and hand over the Letter to the General. There will be a cutscene.
Next Main Scenario Quest
After completing the quest, talk to Bartholomew to accept the next quest: Call of the Sea.