Sooner or later the executive who sponsored your transformation will move on: promoted, reorganized, or simply gone. If the program wobbles the moment they leave, you have learned something uncomfortable about it: it was never institutionalized. It was being personally carried, and the person carrying it has put it down.
Sponsorship is a single point of failure
A strong sponsor is a gift and a risk in the same package. They clear blockers, fund the work, make the calls no one else will. They also become, without anyone deciding it, the reason everyone else does not have to. Authority concentrates around them because that is the path of least resistance. The healthiest question to ask of a sponsor is not "are they committed?" but "would this survive without them?"
Build the transformation so it could lose its most important supporter and keep moving. If it cannot, you do not have a program. You have a favor that has not yet been withdrawn.
Decisions must live in the structure, not the person
You survive a change of sponsor by having put decision rights, cadence, and ownership into the operating model itself, rather than into one person's calendar and goodwill. Written-down authority is portable; personal authority is not. The work of making a transformation outlast its champion is done long before they leave, every time you resist the easy escalation and force the decision to live where anyone could find it.
The handover is a stress test, not a setback
A change of sponsor reveals what is real and what was held together by one person's attention. Treat it as the audit you would never have volunteered for. The dependencies that suddenly look fragile were always fragile; you just could not see them while the sponsor quietly absorbed the strain.
Good sponsors make themselves removable. If yours is irreplaceable, that is not loyalty. It is fragility you have not been billed for yet.