That was supposed to be passed down to me!

That was supposed to be passed down to me!
あれは私に譲られることになっていたのに！

shop that was supposed to open today
今日開店するはず［予定］だった店

forget what one was supposed to say
言おうと思っていたことを忘れる

on the last day that someone was supposed to be in
（人）の～滞在予定の最終日に