If he came from Egypt to visit his father in ad-Dammaam, and was intending to perform ‘Umrah, from where should he enter ihram?
Question

                In sha Allah I am going to go to ad-Dammaam for five days, to see my father who works there; this is my intention.

Question 1: is it permissible for me to change my intention there and enter ihram for ‘Umrah from there?

Question 2: if the answer is yes, do I have to stay in ad-Dammaam for three days before entering ihram for ‘Umrah, or can I enter ihram for ‘Umrah at any time?

Question 3: what is the miqaat from which I have to enter ihram for ‘Umrah and put on the ihram garments?
Praise be to Allah.
    If you are travelling to visit your father, then you decide 
    to do ‘Umrah, there is no stipulation requiring you to stay in ad-Dammaam 
    for three days; rather you can go for ‘Umrah whenever you want, and enter 
    ihram from the miqaat from which the people of ad-Dammaam enter ihram, which 
    is Qarn al-Manaazil (as-Sayl al-Kabeer), near at-Taa’if. 

    The basic principle is that whoever comes wanting to do 
    ‘Umrah must enter ihram from the miqaat, and the miqaat of the people of 
    Egypt is al-Juhfah or Raabigh. But if a person is going to go to another 
    city, such as al-Madinah, Riyadh or ad-Dammaam, it is permissible for him to 
    delay ihram, then enter ihram from the miqaat of the people of the city that 
    he goes to. Please see the answer to question no.
    96758.

    And Allah knows best.