Use the effective appointment, duty allocation and records showing who would take over the previous work. A title change alone leaves the main question unanswered. Ask for the papers that existed before the transfer was contemplated: the organisation chart in force, the delegation-of-authority schedule, payroll records naming the successor, and the minute recording the appointment. Documents created after the plan was formed answer the question less convincingly than documents the business made for its own purposes.
Track the duties that remain
Identify technical or routine work still assigned to the applicant and explain its place in the proposed role. Preserve genuine transition dates. Do not present a planned replacement as an employee already performing the work.
Hypothetical example: a clinical-trial site management lead is promoted to run a United States monitoring group, and her file holds an enthusiastic memo, a signed offer and nothing more. Her adviser asks for the chart showing the monitors who would report to her, the minute recording the successor appointed to her former portfolio, and the payroll entry proving that successor began. Two of the three exist; the replacement has not yet been hired.
She files after the hire rather than before it, so the account of the role matches what the company's own records say. Filing earlier would have meant a description the employer's documents contradicted.