Corel standard version cdr in CMYK, pdf in RGB what is wrong

HI,

I have Corel 2021 Standad.

All my elements are made like CMYK

I must create from cdr pdf to send it to Print House.

But when I make pdf file color change on RGB.

When I open pdf file, all elemnts are like RGB.

What is wrong.

What i must change.