What if the wedding dress building unilaterally changes the photography contract without permission?

In the future, we should have a sense of self-protection and know the relevant laws in advance.

I think you can solve the related problems with the photo studio first. If you can't solve it, you can ask the Consumers Association for help. Finally, you have to file a civil lawsuit with the help of the Consumers Association, because the Consumers Association is more experienced and better than personal reconciliation.

It should be noted that an oral agreement is also a contract, but it needs strong citation. It's not good for you now anyway.