You can reply to the message in a polite and understanding manner. Here's an example of a possible response: "Thank you for letting me know. I completely understand and appreciate the heads up. Let's plan to reschedule for another time that works for you. Have a great weekend too!"

Sorry, something suddenly came up tonight so I have to raincheck on the meeting. Sorry, have a great weekend. "Raincheck at some other time" isn't correct. I can understand what you mean but it doesn't sound natural. Here's one way to think about it: to take a raincheck, or to raincheck, is to take out a debt on the event instead of attending at the planned time. You'll repay the debt by attending or holding the event at a later time. You don't take out the debt at a later time; you take out the debt now and repay it later. "Raincheck" is informal and nuanced, and personally I would only use it here if the meeting is very informal or casual, and if your cancellation doesn't strongly affect the other person. Otherwise, to me it feels a little presumptuous and not very apologetic. Instead, I would say, "I can't make it to the meeting," "I'll have to miss the meeting," or "I'll have to reschedule the meeting" (if you were the one who originally scheduled the meeting).

The style will depend on the level of formality. If you want to sound ‘official’, ‘raincheck’, etc is not right. ‘I regret that, due to unforeseen circumstances, it will not be possible to meet today, and we will hold the meeting at a later date.’ If informality is preferred : ‘ Sorry, something has suddenly come up tonight, so we will have to defer the meeting to another time.’ To have or hold a rain check is what you might say rather than write.

Thank you very much! Is the question correct though? have to rain check at some other time??