He is going to travel to Jeddah and he does not know whether he will be able to do Hajj or not
Question

                I am going to travel to Jeddah for work purposes before Hajj in sha Allah. It is my intention to do Hajj if I am able, but I may not be able to do Hajj because of my work circumstances. From where should I enter ihraam for Hajj? Should I go back to the meeqaat or enter ihraam from Jeddah?.
Praise be to Allah.You do not have to go back to the meeqaat, 
    rather you should enter ihraam from the place where you are when you decide to do Hajj, whether that is in Jeddah or elsewhere. This is because 
    when you passed the meeqaat you were not firmly resolved that you were going to do Hajj.
 Shaykh Ibn Baaz said:
 Whoever comes to Makkah with the intention 
    of doing Hajj if he can, then it becomes possible for him and he decides to do Hajj, should enter ihraam from the place where he is, whether he is 
    within the meeqaat or in Makkah. If he knows that he will be allowed to do that, then he has to enter ihraam for Hajj from the meeqaat which he 
    passes, when he passes it with the firm resolve to do Hajj. The Prophet  (peace and blessings of Allaah be upon him) said: “They [the 
    meeqaats] are for them [their people] and for anyone who comes to them who is not of their people and intends to do Hajj or ‘Umrah. And whoever is 
    living within these boundaries can enter Ihraam from the place where he decides (to do Hajj), and the people of Makkah can enter ihraam from 
    Makkah.” Agreed upon.
Fataawa Ibn Baaz, 
    17/53.