How to remove password for PDF?

I open the password PDF file in Preview but the "Export to PDF" is greyed out. I tried "Export" but it did not remove the password. Pls advise. Thanks https://preview.redd.it/qdh0392joa9e1.png?width=768&format=png&auto=webp&s=7a6f0969db1fb223fbad273eb036fcd8b4a74702