How can I set Powershell check box to False after button click

I am creating a Powershell GUI, I have a Checkbox that will force the user to change password on logon. I have the textbox for the password set to clear and it works fine, but I cannot find a way to uncheck the Box programmatically. I have tried $CheckBoxRLO.Checked -eq $true After the code to reset the password but the box stays checked.