im bored 

thank you based rhyme king you made this possible![]()
Blah Blah Blah Blah Blah Blah Blah Blah [Rhyme A]
Blah Blah Blah Blah Blah Blah Blah Blah [Rhyme A]
Blah Blah Blah Blah Blah Blah Blah Blah [Rhyme B]
Blah Blah Blah Blah Blah Blah Blah Blah [Rhyme B]
Blah Blah Blah Blah Blah Blah Blah Blah [Rhyme C]
Blah Blah Blah Blah Blah Blah Blah Blah [Rhyme C]
etc...
^^^^^ This is a rhyme scheme. It's basically the pattern of your bar/line structure.
When you "Switch Up Your Rhyme Scheme," it means exactly what it says. Switch up the way your writing your bars/lines/rhyme words/raps within your verse
For example. The above verse, if you were to write your lines/rhymes like that for 16 bars straight then of course it would sound repetitive. So what you could do is switch it up every now and then. When, and how often you switch it up is completely your decision.
For example a "Switch in rhyme scheme" looks like this
Blah Blah Blah Blah Blah Blah Blah Blah [Rhyme A]
Blah Blah Blah Blah Blah Blah Blah Blah [Rhyme A]
Blah Blah Blah Blah Blah Blah Blah Blah [Rhyme B]
Blah Blah Blah Blah Blah Blah Blah Blah [Rhyme B]
[Rhyme C] Blah Blah Blah Blah Blah Blah [Rhyme C]
[Rhyme C] Blah Blah Blah Blah Blah Blah [Rhyme C]
Blah Blah Blah Blah Blah Blah Blah Blah [Rhyme D]
Blah Blah Blah Blah Blah Blah Blah Blah [Rhyme D]
Blah Blah Blah Blah Blah Blah Blah Blah [Rhyme E]
Blah Blah Blah Blah Blah Blah Blah Blah [Rhyme E]
etc....
As you can clearly see the "Rhyme scheme was switched up" during the "Rhyme C" bars. Not only can you see this, but you need to realize when you hear it as well. Its just when the artist switches there lyric/rhyme pattern from the previous bars/lines. This not only makes your verse easier to follow, more entertaining, but it can also be more catchy because it gives you a chance to change your vocal tone/delivery.