replace open graph meta

Dear Sir/Madam,

I know how to add custom header using Elements, I did it but I could not able to replace the default meta, the Elements just help to add my custom header but not replace it, please advise how I can do that?

Refer to the screenshot (see private information), as the custom meta header added by Elements, the page finally contains two sets of og meta, how can I remove the 1st set?

This custom meta header is only applied to specific page, so the 1st set og meta header is valid for other pages.

Best regards,

Kelvin.