Here are some examples of natural-sounding sentences in the passive: "I felt called to be a doctor." (the vocation or profession in which one customarily engages) "I was called to the jungle to study gorilla behavior." (a strong inner impulse toward a particular course of action especially when accompanied by conviction of divine influence) https://www.merriam-webster.com/dictionary/calling It's also possible to say, "I hate being called by telemarketers all the time." Using the passive voice here emphasizes my victimization by them.

I would say it is not natural. You would say "school is calling" because you know the person/organisation You might use being called more for things like telemarketers or cold-calls where you don't really know the person/organisation too much. "I am being called by telemarketers all the time". Even then, "I might say I keep getting calls" rather than use the passive voice.

'I am called' sounds odd because it implies that you are on the phone as you speak, which is unlikely - I was called this morning, or I will be called tomorrow is more likely. In the instance of someone calling you now, just say the school is calling, I must take the call. And, yes, use the active again in the other example - the phone always rings at this time, or someone always calls at this time.

Passive voice in English (when you use a past participle, i.e., called, and the subject is not the active role in the sentence) is not wrong, but sometimes it can be awkward (or unclear). Also, using passive voice is more wordy, so it’s not always as direct as the active alternative. The reason passive voice can sometimes be unclear is because it’s easy to omit the subject. For example, if you say “I am being called”, it’s not clear who is calling you (or why). Or even if you do mention the subject passively, you are still directly emphasis away from the subject. Sometimes, this is intentional. In cases where a speaker wants to obscure things (politicians, business leaders, etc.), the passive voice is a powerful tool! :) You also hear this in the news a lot (perhaps when all the facts are not yet known), for example “E-mail messages were deleted from the server of candidate Jones”. Passive voice can be useful, but over-using it should be avoided. And in general, an active voice may be a more clear and direct way to communicate the idea. I am being called from my school. << this is perfectly fine (and natural), but “My school is calling me” is more direct. I am constantly called at this time. << this is fine, too, but it implies you don’t know the caller. I am called... -and- I am answered… << these are probably incorrect (depends on how you end the sentences), and they will be awkward. You could instead say "I have been called..." or “I have answered...”, but again these are less direct.