Terminating a Non-Elective 401(k) Safe Harbor - Limitation on Successor Plan?

[ERISA1]

I believe the IRS has gone on the record to say that a sponsor can end a 3% non-elective safe harbor committment Before the end of a 12 month plan year if the sponsor terminates the plan. I've got someone proposing to terminate such a plan and immediately replace it with 401(k) plan that does not have a safe harbor.

I can't believe this is possible. There must be a rule prohibiting a successor plan. Can any one cite an IRS pronouncement on terminating safe harbor elections and prohibiting successor plans? If you can, can you also tell me what a successor plan is? For example, would that be any plan adopted within 12 months?

Thank you.