Texas is at 'at will' employment law state.  This means, that in absence of written contract, the terms of your employment agreement can change at will.... which means any time one of the parties wants to change a term. For you, this means that if your employer (which is the agency) wants to change the terms... they can, but they have to provide you with advance notice so that you can make the decision whether to continue workings or resign.  They cannot tell you, 'we will pay you holiday pay' one month and then end the policy wihout telling you later.  If you don't agree with the terms, you are free to seek alternative employment.However...this is the general rule in Texas.  A specific, written employment contract can change this.  If the terms of your written contract say they must pay you, then the written contract will controll.