A forum moderator has a duty to all forum users to be fair and impartial, but the obligation to remain a moderator is only to the site owner that hired him/her.
Similarly, as WK Harry owes fealty to all of Winter, but his obligation to remain WK is only to Mab based on the Changes deal. The SK deal with Mab is three tasks in exchange for all debt to Mab ceasing. That means if Harry completes a third favor, his obligation to remain as WK ends.
Apologies in advance for the length of the post. Cozarkian, are you saying that the Changes deal is completely separate from the previous favors/obligation set-up with Mab? I always saw it as a continuation. If so,I am a little confused about the chain of events with regards to this debt.
Harry owes a debt to Lea. He is able to forestall her for a year and a day at the end of GP by taking the poison. Lea is forced to sell that obligation to Mab due to her power increase from accepting the knife from Bianca in GP. Mab comes to Harry in Summer Knight and offers to erase the obligation in exchange for three favors. Harry accepts after a few conditions. The first favor is to act as Winter's Emissary which he completes. Then (in SK) Mab makes the Winter Knight offer:
"We have a traitor among us," Mab purred. "And he will be dealt with accordingly. After which there will be an opening for a new Knight." She watched me and said, "I would have someone worthy of more trust as his successor. Accept that power and all debts between us are canceled."
To me, this means erasing the obligation Mab took from Lea and the two favors Harry owes Mab for that obligation. Mab calls upon Harry again in Small Favor to be her emissary in the matter of the Denarians taking Marcone. She again makes the Winter Knight offer to Harry:
"Unless you should agree to take up the mantle of the Winter Knight," Mab said, smiling. "I should be forced to choose another Emissary if you did, and your involvement in this matter could end." This is followed by:
She tilted her head to one side and stared at me. "One day, wizard, you will kneel at my feet and ask me to bestow the mantle upon you."
"But not today."
"No," Mab said. "Today you repay me a favor. Just as I said you would."
Harry once again completes this task removing another favor leaving one still owed to erase his debt to Mab. Finally in Changes Harry calls upon Mab. He offers to become the Winter Knight with one condition:
"That before my service begins, you restore my body to health. That you grant me time enough to rescue my daughter and take her to safety, and strength and knowledge enough to succeed. And you give me your word that you will never command me to lift my hand against those I love."
Mab accepts, Harry kills Slate, and then Mab and Harry "seal the deal." Granted, at no point do either Mab or Harry mention this taking away the third favor owed or erasing Harrys previous obligation to Mab. Yet, based upon previous encounters this would erase Harry's third favor and his previous obligation to Mab wiping that previous slate clean.
My understanding is that the Winter Knight deal erased the obligation and favors and thus completing another favor will not negate the Winter Knight deal.