The Salesforce development team is strictly following scrum to govern its releases.

The business analyst should tell the executive that work will begin when capacity becomes available. This is because Kanban is a development model that focuses on continuous delivery and flow of work, rather than fixed iterations or sprints. Kanban uses a visual board that shows the status of work items across different stages, such as backlog, in progress, done, etc. Work items are pulled from one stage to another when there is available capacity or demand, rather than according to a predefined schedule or plan. Work will not begin after executive approval is given or in the next sprint because these are concepts that are more relevant for other development models such as change set development or org development. References: https://trailhead.salesforce.com/content/learn/modules/salesforce-business-analyst-certification-prep/user-acceptance https://trailhead.salesforce.com/content/learn/modules/agile-development-with-scrum