Not a lot is written about why or how to retire (disband, discontinue) a certification. Few certifying organizations have policies addressing this potential situation and without a policy, programs tend to linger on, especially when there's politics involved (and when isn't there?).
Here are the minimum components that should be included in a policy and associated procedures:
Circumstances leading to retirement consideration / decision - such as declining trends in number of applicants, number of certificants recertifying, revenue earned, value by stakeholders
Decision - who are the decision-makers and by what margin does a retirement motion get approved
Communications - to whom, how and when will the retired certification decision be communicated
Timeline - in general terms, when will the last application cycle / test administration occur (the key point here is to give sufficient notice to stakeholders)
Future Plan - what happens to individuals already certified (must they cease using the designation at a given point in time, will they be able to maintain the credential indefinitely through ongoing recertification requirements, etc.)
If you are evaluating your certifications on a regular basis (you are, right?!), then you should readily have the data to trigger that certification retirement discussion, when warranted.