Alternately; by turns — taking turns in sequence (used commonly in everyday speech).
長距離ドライブは交代で運転した方が安全だ。
For long drives it's safer to take turns driving.
皿洗いは交代でやってください。
Please take turns washing the dishes.
会議中は司会を交代で務めることにした。
We decided to have the chairmanship rotated during meetings.