Learn Hardcore Korean: sigani eobsdamyeon yaksogeul naeillo mirwodo dwaeyo. - If you don’t have time, you can postpone the appointment to tomorrow.

-(으)면 is the default “if/when” in everyday Korean.
-(ㄴ/는)다면 sounds a bit more hypothetical or tentative (“if it turns out that…”), and can feel slightly more formal.
Here, 시간이 없으면 is the most common in speech; 시간이 없다면 is perfectly correct, just a touch more “if indeed you don’t have time.”

Can I say 시간 없으면 or 시간이 없으면 instead of 시간이 없다면?

Yes. All of these are fine.
- 시간이 없으면: neutral, natural.
- 시간 없으면: casual speech (dropping the subject marker).
- 시간이 없다면: a bit more formal/hypothetical tone.

Why is -이 used on 시간? Could I use -은/는?

시간이 없다 treats “time” as the grammatical subject of “to not exist,” so 이/가 is natural.
은/는 topicalizes/contrasts, so 시간은 없다면 sounds odd unless you’re contrasting it with something else. Stick with 시간이 없다면/없으면 here.

Does 약속 mean “promise” or “appointment” here?

In everyday contexts, 약속 commonly means an appointment/plan/meeting. With 미루다 (“postpone”), it’s clearly “appointment/plan.”

Why is it 내일로 and not 내일에?

-로 marks a new target/destination, so 내일로 미루다 means “move (it) to tomorrow.”
내일에 미루다 is not idiomatic; use 내일로 미루다 (or 내일로 연기하다 in formal contexts).

What exactly does -아/어도 되다 mean in 미뤄도 돼요?

The pattern V-아/어도 되다 = “it’s okay/allowed even if you V” → effectively “you may/can (permission).”
Contrast: 할 수 있어요 = “can do (ability),” not permission.

Is the sentence asking for permission or giving it?

As written, it’s giving permission (“It’s okay to postpone…”).
To ask permission:
- 내일로 미뤄도 돼요? (polite)
- More polite/softer: 내일로 미뤄도 될까요?, …돼도 될까요?

Is 미뤄도 a contraction of 미루어도? And is 돼요 spelled correctly?

Difference among 미루다, 연기하다, and 옮기다?

미루다: everyday “put off/postpone.” Common with 약속/숙제/일정.
연기하다: more formal/official postponement (events, deadlines).
옮기다: “move/shift.” You can say 약속을 (시간을) 내일로 옮기다, but 미루다 is the go-to verb for appointments.

Can I drop particles here?

Can I change the word order?

Yes, as long as elements stay near the verb they modify:
- 내일로 약속을 미뤄도 돼요.
- 약속을 내일로 미뤄도 돼요.
Don’t place 내일로 after 돼요.

How would the passive form look, and what’s the nuance?

약속이 내일로 미뤄져도 돼요. = “It’s okay if the appointment gets postponed to tomorrow.”
Active (약속을 … 미루다) focuses on the person doing the postponing; passive (… 미뤄지다) focuses on the appointment itself.

How can I make this more formal or honorific?

Any pronunciation tips?