Identify the purpose worth keeping
A Sunday dinner may have been intended to see relatives before they travel. If cooking and cleanup are the problem, a short tea visit might still provide the conversation everyone wants. Tell the guests what changes: arrival and departure time, whether a meal is served, and whether they should arrange food before coming. Ask for their answer before assuming they can accept a smaller plan at the same time.
Check the costs that do not shrink with the activity
Check what cannot change. A prepaid ticket, a guest’s long journey, or someone’s care arrangement may make a shorter visit impractical. If the revised plan creates nearly as much work as the original, cancel clearly and agree on the next contact instead of leaving people uncertain.
Cancel cleanly if the smaller version still fails
If guests have bought nonchangeable travel or arranged care for the full evening, a short visit could offer little benefit. Ask whether a new date would suit them better. When cancelling, tell each person who was preparing food, hosting, traveling or covering another duty. Close the old calendar entry and decide whether a new invitation is actually agreed. “We should try again” expresses interest; it does not need a date until people confirm one.