A retailer with stores across several cities needed to replace the mix of systems its locations had accumulated over years of growth. The board’s instinct was a single, clean switchover for the whole estate on one weekend. The operations team’s instinct, born of experience, was dread — because they knew what a system problem during the busiest trading week does to a store that has nowhere to hide. Both instincts were right, which is why the sequencing mattered more than the software.
A big-bang cutover across every store at once would have meant that any single problem hit everywhere on the same day. For a business whose worst weeks are also its most important, that was a risk not worth taking.
The challenges we had to solve
- A trading calendar with busy spells that no store could be migrated through without putting its most important weeks at risk.
- Stores at different levels of process maturity, so a template that suited one would not simply drop into the next.
- The need to run new and old systems side by side during the transition without confusing staff or double-counting sales.
- Store teams who had to keep serving customers while learning a system, with no quiet back office to retreat to.
How we approached it
We built a rollout plan that read the trading calendar as a constraint, not an afterthought. Each store was scheduled into a quiet window for its own location, never through its busiest weeks, and the sequence let us carry lessons from the first sites into the later ones. We hardened a store template on the earliest go-lives, then adapted it deliberately where a location genuinely worked differently rather than forcing a single mould.
For each store we kept the change small and well supported: a short overlap where it was needed, training tied to the actual transactions a till and a back office run, and someone close at hand for the first days. Because only one store changed at a time, any problem stayed contained to a single site we could give full attention to, rather than spreading across the estate.
Where it stands
The whole estate moved onto one system without a store changing platforms during its busiest weeks. Because problems surfaced one site at a time and were fixed before the next went live, the later stores had a noticeably smoother experience than the first — which is exactly what a phased sequence is meant to buy you.