Your question is Refactoring Legacy Code Without Downtime. Take a moment with it on the right.
Talk me through your thinking if you like. When you're confident, submit your answer and I'll grade it like a real screen (7/10 or better passes).
Describe your process for refactoring legacy code without causing downtime. Explain how you would assess dependencies, plan incremental changes, validate behavior, and release safely. Address rollback readiness, monitoring, stakeholder communication, and how you would respond if production behavior differs from expectations.