How to write a resignation letter that's effective immediately? How to Write an Immediate Letter of Resignation?This job aid describes the process for submitting your resignation letter. Resignation is effective as of the date indicated on your S-54 form. Resignations are processed as final and do not continue to pay out over the 12-month cycle. When resigning without notice, your letter should state clearly that the resignation will be effective immediately. Thank you for your service to the public at the City of Dallas. This page contains information as you leave your employment with the City.