席(せき)を立(た)つto leave one's seat

急用(きゅうよう)ができ、席(せき)を立(た)った。

An urgent matter came up, so I left my seat.

誰(だれ)かの話(はな)の最中(さいちゅう)に席(せき)を立(た)つのは失礼(しつれい)だ。

Leaving one's seat in the middle of someone's conversation is rude.

食事(しょくじ)が終(お)わったので席(せき)を立(た)つ準備(じゅんび)をしました。

I prepared to leave my seat since the meal was over.

授業(じゅぎょう)中(ちゅう)に勝手(かって)に席(せき)を立(た)つのは良(よ)くないとされています。

It is considered inappropriate to leave one's seat without permission during class.

公演(こうえん)中(ちゅう)に参加(さんか)者(しゃ)が次(つぎ)々に席(せき)を立(た)つので気(き)が散(ち)ってしまいました。

I got distracted because participants were leaving their seats one after another during the performance.