I had issues converting an Eval server 2019 to a Standard Server 2019, and for whatever reason, it was painful to find the solution. Someone on reddit actually posted about it, so here is me documenting it for posterity!
# ISO Used: 17763.253.190108-0006.rs5_release_svc_refresh_SERVER_EVAL_x64FRE_en-us.iso
# Commands Executed:
DISM /online /Get-CurrentEdition
DISM /online /Get-TargetEditions
DISM /online /Set-Edition:ServerStandard /ProductKey:N69G4-B89J2-4G8F4-WWYCC-J464C /AcceptEULA
slmgr.vbs /upk
slmgr.vbs /ipk <MAK_KEY_HERE>
slmgr.vbs /ato
# Initial Product Key is GVLK (unable to find official source at present)
| Product | GVLK |
|---|---|
| Windows Server 2019 Datacenter | WMDGN-G9PQG-XVVXX-R3X43-63DFG |
| Windows Server 2019 Standard | N69G4-B89J2-4G8F4-WWYCC-J464C |
| Windows Server 2019 Essentials | WVDHN-86M7X-466P6-VHXV7-YY726 |
| Windows Server 2019 Azure Core | FDNH6-VW9RW-BXPJ7-4XTYG-239TB |
| Windows Server 2019 Datacenter Semi-Annual Channel (v.1809) | 6NMRW-2C8FM-D24W7-TQWMY-CWH2D |
| Windows Server 2019 Standard Semi-Annual Channel (v.1809) | N2KJX-J94YW-TQVFB-DG9YT-724CC |
| Windows Server 2019 ARM64 | GRFBW-QNDC4-6QBHG-CCK3B-2PR88 |