Texas Education Code - EDUC § 21.154. Status Under Continuing Contract

(1) resigns;

(2) retires under the Teacher Retirement System of Texas;

(3) is released from employment by the school district at the end of a school year because of necessary reduction of personnel as provided by Section 21.157;

(4) is discharged for good cause as defined by Section 21.156 and in accordance with the procedures provided by this chapter;

(5) is discharged for a reason stated in the teacher's contract that existed on or before September 1, 1995, and in accordance with the procedures prescribed by this chapter;  or

(6) is returned to probationary status, as authorized by Section 21.106.