How much can a company drop your pay at once or the percentage?
Unless you have a contract they can drop your pay all the way to minimum wage at any time, or they can fire you and drop it to zero.
As a Franchise Attorney I agree with the other attorney's answer. Without a contract, employment is "at will," meaning they can lower your pay to minimum wage or even let you go at any time. Consult with a good business or franchise attorney in your area for specific advice.
Mr. Franchise - Kevin B. Murphy, B.S., M.B.A., J.D.
Franchise Foundations, a Professional Corporation