How did the emperor of Lilliput let Gulliver to be sent back to his empire?

From the text:

Three days after my arrival, walking out of curiosity to the north-east coast of the island, I observed, about half a league off in the sea, somewhat that looked like a boat overturned. I pulled off my shoes and stockings, and, wailing two or three hundred yards, I found the object to approach nearer by force of the tide; and then plainly saw it to be a real boat, which I supposed might by some tempest have been driven from a ship. Whereupon, I returned immediately towards the city, and desired his imperial majesty to lend me twenty of the tallest vessels he had left, after the loss of his fleet, and three thousand seamen, under the command of his vice-admiral.

I told the emperor “that my good fortune had thrown this boat in my way, to carry me to some place whence I might return into my native country; and begged his majesty’s orders for getting materials to fit it up, together with his license to depart;” which, after some kind expostulations, he was pleased to grant.