I've booked tickets to visit the Alhambra in Granada. During the booking process, I had to supply the passport numbers of everyone visiting. However, my passport will have expired by the time I intend to visit, so I will have a new passport with a different number. Will this cause me any problems when being admitted to the Alhambra, as my passport number is printed on my entrance ticket.
I visited the Alhambra on two different days in October 2019, and they checked the passports of almost nobody. I witnessed perhaps 50 interactions with customers showing tickets as I waited in various entry lines, and only once did they ask a visitor for their passport. I don't know what triggered the passport check for this particular customer, but he passed without issue.