Different chanters and reeds tune at different frequencies; my Dunbar with a Chris Apps reed tunes right at A=472 Hz. If you're playing a different chanter and reed, we may not be able to be intune at all, although the level of difference can vary from "slightly off on one or two notes" to "oh please stop the horrible noise!" This is why pipe bands specify what chanter and reeds to use, and why band pipers often also have a separate solo chanter for playing when not with the band.