I’ve had good results with the three-options frame: “Given capacity and the 72-hour compliance window we can either 1) hit the two-week date with a reduced scope of A/B, 2) deliver full scope in six weeks, or 3) keep both by adding X resources.” In a meeting and state it once and pause so someone has to choose; in email, list the options with dates and ask for a decision by a specific time so you can plan. Then send a quick recap that confirms the choice, what’s out of scope, and known risks to head off scope creep.