Abdulla bin Abdullah and salim bin Abdullah bin Umar when the army besiged Ibn Az-Zubair before he was killed. They said: "It does not matter if you do not perform Hajj this year; we are afraid lest we are prevented from reaching the House." He Sadi: we went out with the Messenger of Allah and the disbelievers of the Quraish prevented us from reaching the House. So the Messenger of Allah slaughtered his Hadi and shave his head. I ask you to bear witness that I have resolved to peform Umrah. If Allah wills I will set out and if I am allowed to reach the House I will circumambulate it, and if I am prevented from reaching the House I will do what the Messenger of Allah did when I was with him." Then he traveled for a while, then he said: "They are both the same. I ask you to bear witness that I have resolved to perform Hajj as well as Umrah. And he did not exit Ihram for either until he exited Ihram on the Day of Sacrifice and offered his Hadi. (Using translation from Nasāʾī 2859)  

خَرَجْنَا مَعَ رَسُولِ اللهِ ﷺ فَحَالَ كُفَّارُ قُرَيْشٍ دُونَ الْبَيْتِ فَنَحَرَ رَسُولُ اللهِ ﷺ هَدْيَهُ وَحَلَقَ رَأْسَهُ وَقَالَ أُشْهِدُكُمْ أَنِّي قَدْ أَوْجَبْتُ عُمْرَةً إِنْ شَاءَ اللهُ أَنْطَلِقُ فَإِنْ خُلِّيَ بَيْنِي وَبَيْنَ الْبَيْتِ طُفْتُ وَإِنْ حِيلَ بَيْنِي وَبَيْنَهُ فَعَلْتُ مَا فَعَلَ رَسُولُ اللهِ ﷺ وَأَنَا مَعَهُ ثُمَّ سَارَ سَاعَةً ثُمَّ قَالَ إِنَّمَا شَأْنُهُمَا وَاحِدٌ أُشْهِدُكُمْ أَنِّي قَدْ أَوْجَبْتُ حَجَّةً مَعَ عُمْرَتِي فَلَمْ يَحْلِلْ مِنْهُمَا حَتَّى أَحَلَّ يَوْمَ النَّحْرِ وَأَهْدَى