So, the issue is with Sarah, right?
She is not listed with her parents, only Mary.
Sarah is listed with her Husband, which is also correct, right?
Please re-read the Knowledge Base article that I suggested you read.
What will be very helpful, would be to post the Workspace you are in, the Tab in that Workspace, and the Button that you are seeing this information.
For Examaple: People Workspace, Person Tab, Relationship button.
Then providing some details on what you see and what you do.
Simply put, you DETACH people from Incorrect Relationships and ATTACH them to correct Relationships.
It's always a good thing to make sure the Individual is in the Index ONE Time.