Design a phased migration plan for Support without hurting users at global scale

Problem Statement Description

Product context: DoorDash is a local commerce and delivery platform; its products include restaurant delivery, DashPass, grocery and retail delivery, merchant tools, and dasher tools.

DoorDash is migrating its Support experience for grocery shoppers across global markets. This could involve changes to support tooling, routing, automation, agent workflows, escalation paths, refund/credit logic, or the shopper-facing help experience. Grocery orders are especially sensitive because they include substitutions, out-of-stock items, perishables, delivery windows, higher basket values, and coordination among consumers, Dashers, merchants, and support agents.

Your task is to design a phased migration plan that protects user trust and operational continuity while moving from the current Support setup to the new one. Assume the migration must happen across multiple geographies, languages, time zones, and marketplace conditions, without causing a spike in unresolved issues, late deliveries, poor refund experiences, or agent confusion.

This is an execution-focused question. You should focus on how to plan, sequence, govern, monitor, and safely launch the migration rather than proposing the ideal support product itself.

The experience should consider:

- Which users and workflows are most exposed to migration risk, including grocery shoppers, Dashers, merchants, and support agents

- How to phase the rollout by market, order type, issue type, language, channel, or user cohort

- Owners, dependencies, and coordination across product, engineering, operations, support, legal, finance, localization, and marketplace teams

- Go/no-go criteria for each phase, including operational readiness, support quality, SLA performance, and customer-impact thresholds

- Instrumentation and monitoring needed to detect defects, routing failures, backlog growth, refund errors, or negative shopper outcomes

- Rollback, containment, and escalation plans if the migration causes user harm or operational instability

- Communication and training plans for support agents, internal stakeholders, Dashers, merchants, and affected shoppers

- Launch risks specific to global grocery support, including peak periods, regulatory differences, fraud exposure, and marketplace balance

The goal is to present a practical migration plan that DoorDash could execute at scale while minimizing disruption to grocery shoppers and preserving delivery reliability, support quality, and marketplace health.