in texas can an employer lower my pay from 15.00 dollars an hour to 10.00 dollars an hour?

If you are an at-will employee (ie you don't have a contract or are not a member of a union with a contract with the employer) your employer can change the terms and conditions of your employment (hours, work location, pay, duties, position, uniform etc) at any time for any reason or no reason (just not because of your race, sex, age, religion, disability etc.) as long as such change is effective into the future only.  The employer cannot change pay or other benefits for periods which the employee has already worked.  If the employer changes your terms and conditions on a go-forward basis and you show up for work after those changes are put into effect, you are deemed to have accepted them. The one exception to the above, in your particular case, is if your offer letter contains language which expressly restricts the employer's right to do what I just described.  Good luck.