Rain check
 

I received this e-mail, and I don't understand what a rain check is:

I´m sorry but I´ll have to cancel lunch on Friday, can I take a rain check please?
Kisses.
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Can anyone help me?

Can I have a rain check? means can we do it another day? Can we put it off? It's a very common expression. By the way, should I be jealous?:(

Just two tiny corrections.

What Iris said is completely correct. That is what the saying means, even in the 'can I take a rain check' form.

A rain check itself is a vale in Spanish. Here in the states a rain check can be given to a customer when he comes to buy something on sale in a store, but the store has run out of the item. The rain check is a voucher or a promissory note that allows the customer to get the item at the sales price when it is back in stock.

Thanks a lot, Rusty and Iris. I see this lady thinks I'm a store. Next will be to ask for a complaint form.

Sure, Iris, you got it. But, remember, each week has got seven days and seven nights. :rolleyes:

That phrase is actually really common, and it's used in a figurative sense all the time like in the email you got.

I´m sorry but I´ll have to cancel lunch on Friday, can I take a rain check please?

Me da pena pero tendré que cancelar [nuestra cita/la comida] el viernes, [pero vamos a planear hacerlo en otra ocación/pero vamos a ver cuándo podemos hacerlo].

I suspect you're referring to the little form that many stores have, where you can fill out your complaints, comments etc for the store and either deposit it in a box or send it back in the mail. If that is the case, I think it would be called a complaint form, suggestion form, feedback form, evaluation form, or something of the like. Does anyone know what those forms are really called?

All the above. Son encuestas, ¿no?

En español son hojas de reclamaciones. I've seen hundreds of times these at bars, restaurants, hotels... As Spain is a very touristic country, it's obligatory to have these hojas de reclamaciones or complaint forms in every bussiness, although it's not always so.
I think the word is complaint form, can anyone confirm it? Thanks a lot.

Yes, complaint forms is correct.
A little nicer way to say it is 'suggestion form'.