take a raincheck

take a raincheck оn ~ отложить на потом; перенести (приглашение) на другой день

Meaning: politely decline an offer whilst implying that you may take it up later; you mean to say that you cannot accept an invitation or offer now, but you will be happy to accept it at a later date.

Example 1: Can you manage Tuesday? — I'll have to take a raincheck on that, I'm afraid. — Во вторник сможешь? — Боюсь, что придется отложить на другое время./~ Поживём — увидим./~ Там видно будет.

Example 2: Do you mind if I take a rain check on that lunch invitation? I'm going to be away all week.

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A rainckeck was originally a voucher used in the US entitling one to see another baseball game if the original one was rained off.