click on her on the tree and it should give you the option to delete or edit her.
Do you have a Charles Westley who is married to a Fanny or Francis Westley? Charles was born in 1791 I don't know were and his wife was born in Clemsford Essex and was born I think in 1793 or 6. I have info on their children but not who she is I saw her baptism record and I saw her parents first names were William and Elizabeth but no last name on there.
I experienced a similar situation. What worked for me was instead of clicking the" Add son/daughter" buttons, I instead clicked the "Attach existing child button", which opened a new screen with a list of family members. Simply scroll down to the appropriate person, click on the name and follow the prompts.