Re: I have a problem regarding voice and tense
Welcome to Using English.
Your friend is wrong. "I had made changes" is past perfect. "He had made changes" is past perfect.
I need to make these changes -- active.
These changes need to be made -- passive.
I am curious about why you want to use the passive. Are other people going to make these changes?
I'm not a teacher, but I write for a living. Please don't ask me about 2nd conditionals, but I'm a safe bet for what reads well in (American) English.