Yes you can, but since the "add-on"-seal PHPP Ex­pert can only be hold in com­bin­a­tion with the "Cer­ti­fied PH Desiger/Con­sult­ant" cer­ti­fic­ate, you can only use it once you have suc­cess­fully passed the De­sign­er/Con­sult­ant ex­am.