As per the BBC: https://www.bbc.co.uk/news/uk-england-53500449
It's not immediately clear what this means for Anne Sacoolas, but I can't imagine the USA would agree to the amendment if it made her open to extradition and prosecution, so presumably she won't be coming back to the UK to face trial.
For anyone not familiar with the case: https://en.wikipedia.org/wiki/Death_of_Harry_Dunn
The UK and the US have agreed to amend an "anomaly" that allowed Harry Dunn death suspect Anne Sacoolas to claim diplomatic immunity.
A court hearing last month heard the "secret agreement" permitted Ms Sacoolas to return to America after the 19-year-old's death last August.
He was killed in a crash near RAF Croughton, Northamptonshire.
It's not immediately clear what this means for Anne Sacoolas, but I can't imagine the USA would agree to the amendment if it made her open to extradition and prosecution, so presumably she won't be coming back to the UK to face trial.
For anyone not familiar with the case: https://en.wikipedia.org/wiki/Death_of_Harry_Dunn