Can you stretch the leather on the shaft of a leather boot? If so, how?

I bought a pair of leather boots via a catalogue and it is too late for returns. The shoe part fits fine. It’s a zip up boot and the shaft is cut really narrow (they are Italian boots, not made for American calves, apparently.) I am not overweight, but I workout and have more defined calves. It zips halfway up and can’t go further. Is there any way that I can stretch the leather out? Or does a shoe shop/cobbler do this sort of work? Any other solutions? These are really lovely boots and I would like to wear them.

Thanks in advance.

(I’m putting Texas in my topic box…because I know Texans know their boots!)