It looks like you haven't had your code reviewed yet :-)
The goal of the code review is to get code in decent quality, and to know that you have got code of decent quality. When the code of an inexperienced developer is reviewed, then it can be used to teach how to write better code, while avoiding to frustrate that developer.
The reviewer should never change your code. They can make more or less strong suggestions how they would like your code to be changed, and they can decide whether to accept your code or not.
If the review goes right / if I review your code, what you will likely get is some comments how I would write the code which you can learn from, or ignore - these are things where I have an opinion and you are free to have a different opinion. In my area, good naming of functions, variables and so on is considered important, so you may get some suggestions to improve naming. Usually you should make changes in that case (sometimes by finding an even better name for something). Sometimes I'll find bugs. You fix them. Sometimes I'll find things that I thing are bugs, and I'm wrong. If it's hard to see that the code is correct, you make it more obvious correct. If I just got it wrong, you tell me.
If I think that the design is generally not right, then this should have been discussed earlier. We should then think about whether your design is good enough, taking into consideration how much work is involved in a change, or maybe I was just wrong and your design is better. We should end up with agreement.
If reviewer and reviewee cannot agree, then we have a problem. Because it means that one of us is incapable of teamwork, or one of us is uncapable of distinguishing between a good or bad design, or both. This is not necessarily your fault. Unfortunately there are developers who are senior and clueless, and that will be a problem for the company and for you.
If it happens, think very, very hard: Do you have a problem accepting well-founded criticism? If that's the case, you need to change your attitude. Are you too inexperienced to see why the reviewer is right? If that's the case, that's no problem. Trust the reviewer and learn. Are you sure that you know better than the reviewer? Accept the review, but ask a third, trusted developer about his opinion. Remember you can be really sure of yourself and be right, but you can also be really sure of yourself and be wrong.