Kathy Gail Haynes is my sister NOT my daughter I was trying to add her to my oarents[ children not to mine.
I would click on the ID for your sister (Kathy) to copy it. Then go to "Add Child" beneath your parents and choose the "By ID Number" option on the screen that appears. Paste her ID number into the box and click on "Next". This will add her as a child of your parents. THEN, you must return to where she is listed as your daughter and click on the pencil icon alongside her name. Click under "Remove or Replace" and check the box labelled, "I have reviewed the relationships, sources, and notes for these individuals". Click on "Remove parents", add a reason statement in the box that appears, then click "Remove".
It might appear to be a daunting task, but follow the instructions / screens and these actions will place your sister in the correct relationship (with you and your parents) on the Tree.
I'm sure another user will be able to provide a link to a "Knowledge Article" on the process, as there's sure to be another method (possibly more straightforward!) than mine. However, this has worked for me when occasionally I have made similar errors.
On top of what 'Paul' has already proffered ...
Here is a "Knowledge Article" in 'FamilySearch':
How do I correct parent-child relationships in Family Tree?