Round-The-World fare Air Canada date changes?

I have a Star Alliance round-the-world discount special fare with the 5 stop max etc etc. Apparently when I’m on the road I am able to change the dates of flights “for free or for a local service fee”. Does anyone know if Air Canada, or United Airlines charge a “local service fee” for date changes?
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7Proud Muslimah8Beautiful Islam6:Yes, they do. Almost all airlines do.