Go in to Settings and then Apps and doing it from there. I also learned this little trick. If you can't send or receive texts do this.
Dial ##72786#
Enter <your MSL> and hit OK
Click Reset and hit OK
Hit OK again
The phone will reset and you will then be able to Send and Receive texts again.
Sometimes things get jammed up and need to be reset. I hard phone reset won't get the job done here. This is the same as having Sprint do it on their end without the hassle of calling.