Quiero cambiar el formato de una pregunta de un proyecto que ya tiene muchas entradas pero no quiero que me presente problemas con los datos ya registrados
First of all backup your entries to avoid any data loss.
What changes do you need to do? If you remove a question you will lose all the answers to that question. However, renaming a question does not affect existing entries.
To be on the safe side, clone your project, add a few dummy entries and then on the cloned project try to do your changes to see how those changes affect the entries.