Are the changes to personnel or to the accountability of the roles and their function?

If its changes of personnel and the roles have not changed then I don't see any great problem other than getting the new incumbants to read, agree and sign any documentation that the old personnel had signed
e.g. New CEO to sign the H&S Policy & Statement.

It may be that new personnel have a different opinion than old with regards H&S but that you will find out in time and then may need to review your documentation.
If the new brooms start changing management responsibilities regarding H&S responsibilities then you will have to review your documentation.

If the top management "organisation structure" has not been changed, but just a change of the individuals who were in the positions, then you generally are not required to undertake a formal Management of Change process.

However, the incoming team has to be briefed/trained in their duties/responsibitities for HSE Matters.