The manual does not explicitly provide a front-panel 'Initialize' or 'Format' button sequence in the provided text. The closest procedure is clearing data via MIDI or individual Preset Erasure (if available in Edit menu, page 59 lists Erase). Note: Page 125 Index lists 'Initializing the Orbit' but the text for that page is missing from the source provided. I will provide the Erase Preset procedure instead.
Source: Orbit — e-mu-orbit-operation-manual (manual)