You may have a customer that needs to change the insurance type that is listed on the insurance plan. Through insurance validations you can only change the insurance type of the parent, not the child insurance plan. So the customer will think that they have changed their insurance type and would only notice that nothing has changed if they run a list of Active Insurances. 

Currently the best way to change an insurance type at the insurance plan level is from Admin>EDI Set-up>Insurance Maintenance. From this screen you can edit details of the child plan attached to the Account.