Cancel means to stop something with no intent to reschedule.
- They had to cancel tomorrow’s game because of the bad weather.
- to cancel a magazine subscription
- No charge will be made if you cancel within 10 days.
Delay means to put off until further notice.
- My plane was delayed by an hour.
- For sentimental reasons I wanted to delay my departure until June.
- I think we should delay deciding about this until next year.
Postpone means to cancel with the intent to reschedule.
- The game has already been postponed three times.
- We’ll have to postpone the meeting until next week.
- We’ve had to postpone going to France because the children are ill.