If somebody sends an email [STRIKE]cancelation[/STRIKE] cancelling a meeting [STRIKE]email[/STRIKE] and apologizes to you, [STRIKE]so, in return[/STRIKE] [STRIKE]what email you have to write?[/STRIKE] how should one reply?
See my corrections above.
As Tdol said, it depends on your reaction to the email. If you don't mind the cancellation, you could reply with "Thank you for your email. I suggest we reschedule the meeting for [date/time]". If you are not happy, you might reply with "Thank you for your email. It is very unfortunate that you cannot make the meeting. I will let you know the revised date and time soon".
Those work only if you were the person who set up the meeting in the first place. If the other person set it up, there isn't much you can do other than say "Thank you for your email. I have noted the cancellation. Please let me know the revised date and time for the meeting as soon as possible".