Legal Question in Employment Law in New York

Re: Overtime Pay & Pay Decrease

It depends upon your position and job. If you are not "exempt" (essentially meaning a manager)

and receive a salary of approximately 450 a week,

or fall into a category of "blue collar" work,

generally after 40 hours a week you are entitled to time and one half your hourly wage, unless you have contracted to accept a higher salary to work longer hours.

The pay decrease question is too broad; yes a company can decrease pay, unless there is a reason that it is inappropriate, such as age discrimination.