How do you delete a relationship request on facebook?

Its fairly simple, you go onto your profile and scroll to the box below your profile picture which has the heading 'Information' Click on the pencil icon in the top right corner and then click the link saying 'edit information' in the top box called 'basic information' there will be a section called 'Family Members:' you then click the arrow to choose a relation e.g. sister, brother and then begin typing in the relatives name into the box beside it so that you can make a link to their profile.

Hope this helped it helped me!!