The framework.
A working membership software implementation rests on three legs. Lose any one and the stool falls over. The legs aren't optional, and they aren't interchangeable.
Leg 1: your users. The lodge secretaries, treasurers, membership chairs, members. The people who use the software every day to do the actual work of the organization.
Leg 2: your staff. The Grand Secretary's office, your executive director, or whoever holds the institutional knowledge of how your organization actually operates. The people who answer the questions only your organization can answer.
Leg 3: your software vendor. The company that built and maintains the platform. The training, support, documentation, and platform know-how that lets users actually do their work.
Each leg has a job that no other leg can do. Each leg can fail in its own way. Most organizations have problems with their software because one of the three legs is too short, missing, or trying to do another leg's job.