PurposeThis paper aims to outline the transition of two libraries from one automated interlending system (OCLC VDX) to another (Relais ILL).Design/methodology/approachThe paper provides historical background and context for the change, the transition planning, processes undertaken to ensure success, and the challenges and lessons learned along the way.FindingsThe authors report that, although the transition process went fairly smoothly, libraries planning for a similar transition should build some flexibility into their overall planning process and be prepared to pay close attention to their communication processes.Originality/valueLibraries planning a transition from one interlending system to another will find this paper quite useful. Any library using either the VDX or Relais interlibrary systems will find the appendix of comparable ISO ILL terminology helpful as well.