Attorney appointments are made by U.S. magistrate judges. You will be notified by a courtroom deputy of your appointment to a federal criminal case. You must be prepared to be available on short notice for preliminary matters (e.g., initial appearances and detention hearings).
All appointments include representation on appeal and petitions for certiorari. If a conflict arises, you may be given permission to withdraw by the U.S. district judge presiding over the case.
See Chapter 2 of Volume 7, Part A of the Guide to Judiciary Policy, for additional information on the appointment process.