European football’s governing body gave City a two-year ban from their club competitions in February for “serious breaches” of Financial Fair Play regulations.
The ban was overturned by the Court of Arbitration for Sport last month.
Pep Guardiola said in July City deserved an apology, but Khaldoon said: “Life is too short to carry grudges.”
Speaking to club media, he added: “It is one of the most prestigious competitions in the world of sports and it is a competition we want to win and it is a competition we have to respect in order to win.
“And this was a challenge, it’s behind us, end of the story. I am focused on one thing: how I can help this club compete in this competition and win it and how to have a constructive relationship with Uefa. I think it’s the only way to go.”
Man City’s hopes of winning the Champions League this year were ended by Lyon who defeat them 3-1 in the quarter-finals, while they finished second in the Premier League.