You can resign from your position in federal service at any time; you do not need agency approval to do this and you do not need the agency to “grant” you a resignation. However, you would not want to “request removal” because in essence, you are asking to be removed (fired).
A Ward violation (Ward v. USPS, 111 FMSR 183 (Fed. Cir. 02/17/11) occurs when a deciding official considers information not previously noticed to the employee via the proposal notice.
Office of Personnel Management regulations permit agencies to place employees on indefinite suspension pending completion of criminal proceedings.