You modulate your voice when you change pitch, like when your voice goes up at the end of a question. 
Just like with music, its rhythm and tone can convey a meaning that may be different than the literal interpretation of your words.

Being able to modulate your voice correctly...

• If you want your audience to quiet down, to be calm or to perhaps hang on your every word, speak more quietly.
• f you want to rile up your audience, speak with a stronger voice. You can also use volume to convey your passion.
• Try not to s...

When you decide to make a career switch on your own terms, there will be highs and lows, and moments of clarity followed by clouds of doubt. 

Expect this, and it will feel like a part of the ride versus a dead-end.