Is there a way to unread a letter in Dragon Age 2

Hi everyone.  I have been playing Dragon Age 2 full time the last 3 weeks and got well into act 3 before I found out that once you read a letter from Orsino that is on your desk, it automatically starts that quest the next time you visit the Gallows - even if you are not done with half of the quests.  Unfortunately, not knowing this, I did not save the game before reading the letter.  Does anyone know if there is a cheat that will permit unreading the letter?