Replace and Trim videos without breaking existing links is a new Microsoft Stream feature. Microsoft will roll this feature out soon.
Owners and admins will be able to replace existing uploaded videos or live events with a new video file maintaining the URLs, embed links, title, description, view counts and likes. Additionally, a new flow for trimming an uploaded video or live event will be available directly in Stream.
Microsoft will be gradually rolling this out to customers in mid-August, 2019, and the rollout will be completed worldwide by the end of November 2019.