There is no more CO PC. Check to see (depending on how you are in Business class - you'll need to check the rules) if you can use the UA Arrivals Lounge - it is airside between the int'l arrivals and the UA domestic terminal. The UA RCC (there are two of them, one in the int'l terminal and one in the domestic UA terminal) may let you in with a same day business arrival. I believe your only shower option is the UA Arrivals lounge. There is a pay-per-use shower service in the int'l terminal (by an independent vendor).

The airport has free wi-fi. If you completely strike out (i.e., no Arrivals access, and RCC denial), you might want to simply pay for the shower service, and then hang out in the G-gate portion of the international terminal. Decent dining options and a lovely public space. It is within the same airside security as UA domestic.

OOPS - I didn't see the originating airline - I assumed UA. you can't use the Arrivals lounge. But you might get RCC access re: star alliance reciprocity.