Learn Hardcore Japanese: yotei ga henkousarete mo, otituite ugokeru you ni naru hazu da. - Even if plans are changed, we should come to be able to act calmly.

V + ようになる: change of state/ability (result).
V + ようにする: make an effort/try to V ( <a class="border-b border-dotted border-blue-400 dark:border-blue-500 cursor-pointer text-inherit no-underline" href="/grammar/japanese/nuance/tsumori-intention">intention /habit).

The passive lets you talk about the plan being changed without naming who changes it (which is often unknown or unimportant). It also sounds a bit more formal. Active is possible if you name the agent:

Passive (impersonal/formal): 予定が変更されても = even if the plan is changed.
Active (with agent): 誰かが予定を変更しても = even if someone changes the plan. Natural and common alternative without passive: 予定が変わっても (intransitive “change,” neutral and everyday).

Why not say 予定が変更しても?

Because 変更する is a transitive verb: you change something. The plan can’t “do” 変更する by itself. You need either:

Transitive with object: 予定を変更しても (someone changes the plan), or
Passive: 予定が変更されても, or
Intransitive: 予定が変わっても.

What exactly does 〜ても mean here, and how is it formed?

V-て + も means “even if...” (concessive condition). It sets up a hypothetical situation that doesn’t stop the main clause from being true. Here, 変更されて + も = “even if (it is) changed.” It’s not about sequence; it’s a condition that concedes an obstacle.

Why is が used with 予定 instead of は?