Change ends after games 1, 3, 5 and subsequent odd games in a set; during a tie-break, after each six points. Those are the standard FIP Rule 5 intervals.
Count the games played, not one pair’s score
At 2–1, three games have finished: cross. At 2–2, four have finished: stay. At a 6–3 set ending, nine have finished: cross. After 6–4, stay for the next set’s first game, then cross.
Changing ends is not always a break
FIP Rule 2 allows up to 90 seconds at ordinary changeovers and 120 between sets. There is no rest after a set’s first game or during a tie-break; its end change allows 20 seconds. Confirm any event-specific format with the organiser.
The tie-break guide handles serving order. Here the useful distinction is simpler: the instruction to move does not necessarily include time for a long discussion. Save a fuller conversation for an appropriate break.
The court from the other end
Three games played. In this imagined outdoor match, one pair have won all three. They cross to the other end carrying a lead and a story about it: their returns are finding space; their opponents are beginning to hurry.
Now the light meets the leading pair differently. A high ball is harder for one partner to follow. From here, the background that had framed each opponent has changed. The court has not become another court. A few things they had stopped noticing are asking for attention.
Wheel of Fortune belongs near this crossing. The Oracle gives temporary conditions their movement without making them a verdict on the people inside them. The pair can have earned their lead and still have more to learn about how it came. Neither luck nor skill explains every part of a run.
One partner says, “Same again.” The other shades their eyes. Agreement will need to include what each can see now.
Across the net, the pair who lost the three games are also taking their places. They bring the same score from a different end.
A question for the new end
“What is different from here?” might be more useful than asking whether the momentum has gone. Light, background and each partner’s view are things you can compare. The question leaves room for an answer other than the story the score has suggested.
That habit begins in the warm-up and continues when you meet unfamiliar opponents.