The spreadsheet is rarely the original problem. It usually began as the quickest sensible way to organise the work, then accumulated formulas, conventions and exceptions until it became an application without the safeguards of one.
The same happens with shared inboxes and paper processes. They work while a small group can carry the missing context in their heads. Growth, absence or audit pressure exposes the dependency.
What we preserve
Replacement begins with the process as it is actually performed. We trace the workbook formulas, informal handoffs, approval rules and exceptions before deciding what the new system should do. Useful behaviour is carried forward; accidental complexity is not.
What changes
The new system gives each item an owner, a status and a history. Rules move out of hidden formulas and into tested code. Several people can work at once, permissions are explicit, and reporting comes from the same records used to run the operation.
Automation handles routine movement and calculation. Cases that need judgement are sent to a person rather than forced through an unreliable rule.
Moving safely
Historic data is cleaned and reconciled before import. Where the process is sensitive, old and new can run side by side until the outputs agree. The spreadsheet is retired only after the replacement has proved that it covers the real work.
This work is normally delivered through Build operational software, with integration and automation added where the process depends on other systems.