Organization restructure

Good Day Community

We are currently under going organizational restructuring and would like to ask anybody whose company has gone through a restructuring process where some departments are faced out and some departments merge.

My question is how did you deal with the general ledger in cases where the financial year had already begun. did you create a new chart of accounts for the new structure and ceased using the old COA? if yes how did you deal with reconciliation, reporting at the end of the financial year. As for HR the plan is to create totally new department under the same organization (meaning we do not want to create a new organization - top level).