Dear Mr./Ms. Bossname,
Please accept my resignation, effective upon completion of the Johnson project.
The team and I mapped out what is left to do, and our best prediction is that the project will be done in three to four weeks’ time. If the timeline changes, I’ll let you know immediately. I will of course also stay on for the presentation to the client.
Thank you for the opportunity to work with such an innovative company, with such rewarding projects.