Make check-box parameter unable for input

Hi all,

I want to make hide or unhide for check-box parameter based on input selection, this is for report.

For example: I have input parameter sales organization p_vkorg. If user enters sales org 'SG10', it will make that check-box is ready for input, if this is other than 'SG10', the check-box field will be disable.

How can we control this?

thanks alots

Alia