Change Consulate Location

My friend (US citizen) filed documents to get a green card for her mother (mother is in Russia) to come to US and get a green card.
USCIS has approved her case in March, 30 2020 (a year ago).
Now the case is in the NVC. No response from NVC so far.
Due to serious deterioration of US-Russia relationships all US consulates in Russia officially stopped issuing any non-immigrant visas.
Immigrant visas are supposed to be issued, but, in reality, they are not issued as well.
So, the case is in "limbo".
My friend wants to ask NVC to set up an interview with her mother to a consulate outside of Russia.
Any advice on how she can do that?
Thank you in advance.
 
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