مناسك حج - مكارم شيرازى، ناصر - الصفحة ٣٦ - Conditions of Hajj al -Tamattu

Article ٢٨- Whenever a pilgrim goes out of Mecca after performing Umrah without Ihram and pasts Miqats, then in return he/ she should become Muhrim( a person who is in state of Ihram )from Mecca and perform Umrah, unless his/ her return is on the same month that he/ she has leaved Mecca) for instance, a pilgrim has leaved in Dhul- Qadah and has returned in Dhul- Qadah (.

Article ٢٩- A person whom his duty is to perform Hajj al- Tamattu cannot return to Hajj al- Ifrad or Hajj al- Qiran, unless the there is not enough time available in the way that this person cannot finish Umrah and join Hajj. In this case, the pilgrim can leave" Hajj al- Tamattu" and make intention for Hajj al- Ifrad or Hajj al- Qiran, and performs the duties of Hajj and after finishing Hajj performs Umrah al- Mufradah( similar to other persons who perform Hajj al- Qiran and Ifrad )and the purpose of not having enough time is that pilgrim cannot perform Wuquf in Arafat from noon until the sunset of the day of Arafa.