明日の予定をキャンセルしたいって英語でなんて言うの？

I'm going to have to postpone our meeting tomorrow. - this response implies that the meeting can be rescheduled. I'm going to need a rain check. - This is a common phrase used in English to express how you're not going to be able to make it, and need to reschedule the outing.

A rain check is used to tell someone that you cannot accept an invitation now, but would like to do so at a later time. You can also use it if you have already accepted the invitation, you can still use the phrase. When you have to cancel a meeting, appointment or date, and something that takes precedent, then you can say "something came up", then provide a response as to why you must cancel.

I am afraid I won't be able to attend tomorrow's meeting. Here you are explaining that you are sorry that you will not be able to go to the meeting Attend- to go to or be present at a meeting, event... Unfortunately, I can not make the meeting tomorrow. 'Unfortunately'- unluckily, sadly, regrettably, unhappily- you are sad that you can not go to the meeting 'Can not make'- you can not go to, you can not attend

It is important to consider the relationship that you have with the person you are supposed to meet. If they are a good friend, you could use more casual language. 'Something has come up' is an informal way of saying that you cannot meet them because you need to do something else. This would not be appropriate with a business associate. 'I'm sorry to say I cannot make it to our scheduled meeting tomorrow' would be a polite way to say you need to cancel, but if you value the relationship, it would be good to ask to 'reschedule' the meeting for a different date. Otherwise the other person may get the feeling that meeting them was not important to you. For example: 'I'm sorry to say I cannot make it to our scheduled meeting tomorrow. Is there any possibility that we could reschedule to another day later this week?'

I am so sorry but I have to attend to something and am unable to meet with you tomorrow as planned. First apologise to the person and then explain why you are no longer able to meet. You do not have to go into detail and therefore it is perfectly acceptable to simply say that you have to attend to something urgently. I'm afraid that I am no longer able to meet with you as scheduled as something urgent has just popped into my diary. Afraid usually means scared but in this instance it's more a term which indicates regret. A similar expression is "I'm sorry." If something has popped into your diary it means that you have just been notified of another meeting or errand. An errand is a task or an assignment. Oh shoot! I can no longer meet with you tomorrow as something has just come up. Oh shoot is a very casual term which is a polite way of saying something like "damn." This is not to be used when speaking to business acquaintances. If something has come up then it means that you have just been made aware of the fact that you have to be someplace else or do something that cannot wait.