If you are asking about Publisher Sets, you can set the destination by right clicking on the Set Title Header and it will open a dialogue which has a place to set a default path for save location. If you are asking about saving individual PDF's then no you can't.
Cheers,
Gerald Hoffman “The simplification of anything is always sensational” GKC Archicad 4.55 - 27-6000 USA 2019 MacBook Pro-macOS 15.0 (64GB w/ AMD Radeon Pro 5600M GPU)