If a thesis committe member asks for changes in my thesis does that mean I'm not getting a PhD "summa cum laude"? I am a PhD student in Germany. I had a question regarding the summa cum laude mark for my thesis. 

To open the examination procedure, I asked three reviewers to read my thesis (my main supervisor and two external reviewers). Now it seems my reviewers evaluated my thesis and they sent their mark to the university. I received a letter form the PhD committee that now the chair of my oral examination will fix a date. Together with this letter, I have received another letter from one of the reviewers. The reviewer asked for some changes in the introduction part of the thesis. 

My question is:
If the reviewer requests for changes, does it mean that he did not give the best mark? I know that all three reviewers of the thesis, beside four members of the examination committee, should gave me the same (best) grade to receive the summa cum laude mention.
I can only speak about the German system, but here it is mostly standard that some relatively minor changes (often stylistic) are requested. Usually, that is done after the oral examination / defense and has absolutely no impact on the grade.


  If the reviewer requests for changes, does it mean that he did not
  give the best mark?


You cannot infer anything regarding your final grade from this. You should concentrate on your oral examination since that is more likely to impact your grade (if you botch it). If you are really anxious about the requested changes, ask your advisor informally if the requested changes indicate a lower grade. Your advisor will probably be able to alleviate your concerns easily.

Keep in mind that summa cum laude is a big achievement but ultimately it doesn't matter much for your future career. Your network and your publications are much more important and nobody can take them from you.