Changes were made all the time. Different scribes did it different ways. The earliest manuscript of John has over 400 scribal changes just within that one document.
I have no idea what “scribal change” means unless you are referring to copying errors, which were not uncommon but we have so many manuscripts of NT that they are easy to spot. 95% of all variants among manuscripts are spelling differences and word order difference - which is easy to occur with Greek, the meaning is the same. In Koine Greek there are at least a dozen different ways you could correctly write “ John loves Mary.” Most of the other variants are scribes accidently skipping a line and leaving it out or mistaking someone’s handwritten margin comments as part of the text and including it in the copy as part of the scripture. We can be confident that 99% of what you read today in a good translation is what was written by the author.