A long-standing supplier refuses to accept the terms of a new agile contract because they don't understand it and believe their history exempts them. What should the project manager do?

The best approach is to train the supplier in agile approaches. This addresses the root cause of their refusal—lack of understanding—and leverages their existing relationship and experience. Agile contracts can be unfamiliar, and educating a valuable, long-standing supplier helps bridge this knowledge gap, fostering collaboration and ensuring project success. Changing contract terms to accommodate their resistance would undermine the agile framework and its benefits. Issuing an RFP for new suppliers is a drastic measure that discards a valuable existing relationship and incurs significant time and cost. Asking the team to perform the work until a supplier is available is a temporary fix that overburdens the internal team and doesn't resolve the long-term need for external support.