Check the published player limit
Look at the rulebook and edition you own. An expansion may increase capacity, but only if you have the required components and use its rules. Adding spare pieces to a game that supports fewer players can change resource availability, turn order and the end condition. It is not a neutral adjustment.
If the game has not begun, changing to another suitable title is usually straightforward. Explain the practical reason without making the new arrival feel responsible for ruining the evening. The purpose of the gathering is to play together; the planned box is a means of doing that.
Do not add a player casually midgame
Once play has started, a new participant may lack the resources, information or opportunities everyone else received. A published joining procedure is useful when one exists. Without it, finish the current short session and include the guest in the next one, or discuss whether the whole group wants to stop and restart.
A guest who wants to watch can sit where they can see public information without looking into private hands. Ask whether they would prefer a drink and conversation away from the table instead. Watching is an option, not a punishment for arriving later than expected.
Consider a different group arrangement
If the total now supports two comfortable tables, offer a split with suitable games and willing teachers. Check that both tables have something people actually want to play. Do not automatically send the newcomer and the least assertive guests to a spare table with an unfamiliar game.
For team play, use a published team mode if available. Two people sharing a position may discuss choices more slowly and gain different information from one player acting alone. If you choose an informal shared position for a learning session, obtain everyone's agreement and be clear that it is a house arrangement rather than a standard player-count rule.
Consider whether the guest knows either proposed game. A split that leaves them as the only newcomer with nobody prepared to explain can be less welcoming than waiting for the current short game to finish. Introduce them to the people at their table and describe the plan, rather than sending them toward an unopened box while the original group resumes.
Revisit the time and space
An added player can lengthen a sequential game even when the rules support them. Recheck the available evening instead of assuming the old estimate still fits. If the group includes first-time players, allow for their explanation as well. A shorter game may now be the more comfortable choice.
Move chairs and personal play areas before setup resumes. Make sure the added seat has a usable view and reach, not simply the last corner of the table. Redistribute common supplies where appropriate and verify any setup changes tied to player count.
Keep the decision brief and inclusive
Offer a small set of workable alternatives: finish this short game and join the next, change games now, or split into two groups. Ask what everyone prefers without inviting an unlimited search of the collection. A clear practical choice avoids a long discussion centred on the unexpected guest.
For future invitations, clarify whether people should check before bringing another person. This is about preparing enough seats and suitable games, not making the gathering formal. A quick message beforehand gives the host time to choose something that accommodates everyone comfortably.
