‏البيوع : Hadeeth No:3658 Ibn 'Umar (Allaah be pleased with thcm) reported Allaah's Messenger (sallAllaahu alayhi wa sallam) as saying: When two persons enter into a transaction, each of them has the right to annul it so long as they are not separated and are together (at the place of transaction) ; or if one gives the other...

‏الحج : Hadeeth No:2859 Ibn 'Abbas (Allaah be pleased with them) 'is reported to have said: The Messenger of Allaah (sallAllaahu alayhi wa sallam) put on Ihigm for Hajj. When four days of Dhu'l-Hijja were over, he led the dawn prayer, and when the prayer was complete, he said: He who wants to change it to Umra may do so....