The old and new processes are both running, so the team assumes it has a safety net. In practice, two versions of the client record now disagree. Parallel running needs a defined purpose, authoritative-record rules, reconciliation and an exit decision. Running both routes without those controls can create another transition problem.
APM's handover research provides context for operational transition. The agreement below addresses temporary coexistence after the rollout approach has been chosen. It does not replace the earlier decision about phased versus coordinated delivery.
Photo by Rodrigo Rodrigues | WOLF Λ R T on Unsplash.
Define why both routes are needed
State whether the old route remains operational, provides a comparison or holds historical reference only. Those are different states. A reference archive should not quietly become another place to enter new work.
Identify which cases enter each route and what users should do when they receive conflicting instructions. Avoid relying on people remembering a verbal exception from the launch meeting.
Write a temporary operating agreement
Include:
Purpose and scope of parallel running.
Case eligibility and authoritative record for each stage.
Who creates, changes and closes records.
Reconciliation method and review frequency.
Conflict owner and permitted correction route.
Additional staffing or effort required.
Exit criteria, decision-maker and latest review date.
Treatment of unfinished work when the old route stops.
Specialist data, access and retention decisions need their appropriate owners. Do not overwrite uncertain records merely to make both views match.
A hypothetical reporting transition
A service business introduces a new reporting workflow while retaining the previous pack for comparison. The old pack uses an earlier cut-off and includes a cancelled case. The figures differ, but that does not automatically prove the new method is wrong.
The owner checks definitions, periods and source records. The team resolves the intended treatment, records the explanation and adjusts the relevant route. It does not copy the old total into the new report to remove the visible disagreement.
This illustrates why reconciliation needs judgement and clear meaning, not only a rule checking whether two totals are equal.
Count the temporary work honestly
Parallel preparation, comparison and correction consume capacity. Include them in the operating plan instead of expecting staff to absorb them indefinitely. Check whether the arrangement is producing the evidence that justified it.
If the same discrepancy returns, investigate the underlying definition or update route. A daily manual correction can hide a design issue that prevents a clean exit.
Close the temporary state deliberately
Confirm the exit evidence with the authorised owner. Communicate which route becomes authoritative, how old links are withdrawn from new work and who handles remaining exceptions. Follow approved arrangements for retained records and access.
Do not end parallel running merely because its planned date arrived, or keep it forever because nobody owns the decision. The small-team project plan connects transition work to the schedule. For the connected task, read Phased Rollout or Big-Bang Delivery: How to Choose. If old and new routes are creating conflicting work, discuss your project requirements.
