[Gretl-users] Trouble changing sample in a script

Hello, I am having trouble changing the sample period in a script file. I initialy set the sample using smpl 1967:1 2007:4 Then latter in the script I set the sample to smpl 1967:1 2011:4 But when I estimate a VAR the sample period remains 1967:1 - 2007:4 I have also used the command smpl --full with the same results. The sample period does not change for the estimation. Two questions: Can the smpl command be used in a loop? What is the correct way to change the sample period in a script?