Praise be to Allah.
You have to enter ihraam on behalf of yourself from the meeqaat which you are going to pass, then when you have completed ‘Umrah for yourself, by doing tawaaf and saa’i and cutting your hair, go out to al-Tan’eem or another place outside the Haram (sanctuary), and enter ihraam for ‘Umrah on behalf of your father. Say, “Labbayk Allaahumma bi ‘umratin ‘an abi (Here I am, O Allaah, for ‘Umrah on behalf of my father).” Then do tawaaf and saa’i, and cut your hair or shave your head, but shaving is better. You do not have to go back to the meeqaat to enter ihraam for ‘Umrah on behalf of your father.
Shaykh Ibn Baaz said:
If you want to do Hajj or ‘Umrah for yourself or for someone else who has passed away or who is unable to do it because they are very old or suffering from an incurable sickness, then you have to enter ihraam from the meeqaat which you pass when you are intending to do Hajj or ‘Umrah. When you finish the actions of ‘Umrah or Hajj, there is nothing wrong with you starting ‘Umrah for yourself from the closest point outside the Haram, such as al-Tan’eem or al-Ji’raanah or elsewhere. You do not need to go back to the meeqaat, because ‘Aa’ishah (may Allaah be pleased with her) entered ihraam for ‘Umrah from the meeqaat of Madeenah with the Prophet (peace and blessings of Allaah be upon him) during the Farewell Pilgrimage, then when she finished her Hajj and ‘Umrah she asked the Prophet (peace and blessings of Allaah be upon him) permission to do ‘Umrah on its own, and he told her brother ‘Abd al-Rahmaan to take her to al-Tan’eem, and she did ‘Umrah after Hajj. He did not tell her to go back to the meeqaat. She had joined Hajj with the ‘Umrah for which she had entered ihraam from the meeqaat as the Prophet (peace and blessings of Allaah be upon him) told her to do, when she began to menstruate before she could do the rituals of ‘Umrah.
And Allaah is the Source of strength.
Fataawa Ibn Baaz, 17/15.