Modify page table entry on Windows

For a stack address I have the following PDE / PTE info from Windgb:

    kd> !pte 6EFFC 
                VA 0006effc
    PDE at C0600000            PTE at C0000370
    contains 0000000065D39867  contains 0000000000000020
    pfn 65d39     ---DA--UWEV  not valid
                        DemandZero
                        Protect: 1 - Readonly

How does WinDBG find out about the readonly state if even the PTE is not valid and how can it be changed? Has to be done via VAD?