However, I'm happy to help out however I can in the next two weeks." If you haven't landed a new gig yet or your new start date is negotiable, know your limits. If you're willing to stay an additional three weeks, for example, don't let your manager talk you into staying three more months.
Or meet up with said colleagues at an industry event, because the world is awkwardly small. So it's in your best interest to make sure that your resignation letter is clear, concise, and polite. Here are some best practices you can follow to make your big exit a professional one.