Take a rain check Informal

To decline an invitation or offer for now, while indicating a wish to accept it at a later, unspecified time instead.

It’s a polite, friendly way to say no to something without closing the door on it permanently.

The phrase comes from American baseball in the late nineteenth century, where a “rain check” was a ticket stub or voucher given to spectators when a game was called off or interrupted by rain, allowing them to attend a future game for free instead of losing the value of their original ticket. The figurative sense, asking for a “rain check” on any social invitation or offer one can’t accept right now, developed naturally from this practice and is documented in general English by the early twentieth century, extending the fairness of the baseball system — you don’t lose your chance, just postpone it — to everyday social life.

I can’t make it tonight, can I take a rain check?

She took a rain check on the coffee invite since she was swamped with work.

Let’s take a rain check on the hike, the weather looks terrible this weekend.

A: Want to grab lunch today? B: I’ll have to take a rain check, sorry.