If I already have a ticket purchased in my name, I can get another without affecting the first

Yes. You can buy as many as you want. The ones you have bought do not affect you. Remember that there are two settings :. General entrance and assigned chairs. If you bought with assigned chairs, you must buy some fences from your location. Or if you get better together.

You buy the position or the seat, what you have to do is that I give it to you together, I say if you prefer.

Not affected