The only mention I can see on the O/S is it's open to fans with Covered End tickets. Also what time does it open & can you get in if you show your S/T as your mate will have your match ticket?
"Supporters are asked to be aware that Bartrams Restaurant and Bar will be closed, though supporters with a valid ticket in the West stand can access the Millennium Lounge and those with a valid ticket in the Covered End will be able to access the Fans Bar."
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https://www.cafc.co.uk/news/view/5e0de9eadfa99/fa-cup-preview-charlton-v-west-bromwich-albion