I am a beginner and I have the opportunity to purchase an upright piano from a friend who no longer uses it; I would like to ask you for information regarding transport: given the limited space of my house's L-shaped hallway, would it be possible to rotate the instrument on its side to get it through? In a horizontal position, there is not enough space to turn the corner.
By rotating it on its side, with the keyboard vertical, could this cause damage or is it common practice in case of difficult spaces?
You absolutely must call a company specialized in piano moving. They will surely solve the problem. There will be no damage by rotating it, but it must be secured and handled by movers who know how to do it. The piano has a certain imbalance and it is dangerous to transport it without having experience in this. An ordinary mover would also run a risk without the proper equipment (special straps, etc...)