The pilgrim who is doing tamattu’ is the one who enters ihraam for ‘Umrah during the months of Hajj and ends ‘Umrah, then enters ihraam for Hajj in the same year. 

One of the conditions of tamattu’ is that the pilgrim should not leave Makkah after ‘Umrah and go back to his own city. If he goes back to his city then comes back to do Hajj then he is doing ifraad, not tamattu’. He does not have to offer a sacrifice because he set out on a new journey for Hajj. If this pilgrim wants to do tamattu’ then he should enter ihraam from the meeqaat when he comes the second time for Hajj. 

But if he traveled from Makkah after ‘Umrah to a city other than his own, such as if he traveled to Jeddah then came back in ihraam for Hajj, then he is doing tamattu’, and his trip to Jeddah does not invalidate his tamattu’, because he did not go back to his family.
Shaykh Ibn Baaz was asked about a man who did ‘Umrah in Shawwaal, then went back to his family, then came back to Makkah with the intention of offering Hajj only – is he doing tamattu’ and does he have to offer a sacrifice? 

He replied: 

If a person does ‘Umrah in Shawwaal then goes back to his family, then comes to do Hajj on its own, then the majority of scholars are of the view that he is not doing tamattu’ and he does not have to offer a sacrifice, because he went back to his family then he came back to do Hajj on its own. This is the view that was narrated from ‘Umar and his son (may Allaah be pleased with them both), and it is the view of the majority. It was narrated from Ibn ‘Abbaas that the pilgrim in this case is doing tamattu’, and that he does have to offer a sacrifice, because he combined ‘Umrah and Hajj in the months of Hajj in the same year. But the majority say that if he goes back to his family – and some of them say that if he travels a short distance – then comes back for Hajj on its own, then he is not doing tamattu’. It seems, and Allaah knows best, that the most correct view is that which was narrated from ‘Umar and his son (may Allaah be pleased with them both), which is that if he goes back to his family, then he is not doing tamattu’, and he does not have to offer a sacrifice. But for the one who came to do Hajj and did ‘Umrah and then stayed in Jeddah or al-Ta’if, and he is not one of their people, then he entered ihraam, this person is doing tamattu’, and the fact that he went to al-Ta’if or Jeddah or Madeenah does not mean that he is no longer doing tamattu’, because he came to perform them (‘Umrah and Hajj) together, and he only went to Jeddah or al-Ta’if for a reason. The same applies to one who goes to visit Madeenah – this does not mean that he is no longer doing tamattu’ according to the most obvious and most correct view. So he has to offer the sacrifice of tamattu’ and do saa’i for Hajj just as he did saa’i for ‘Umrah.  

Majmoo’ Fataawa al-Shaykh Ibn Baaz, 17/96 

In Fataawa al-Shaykh Ibn Baaz (17/98) it also says: 

If he comes back in ihraam for ‘Umrah – i.e., on his second trip – and exits ihraam then stays until he does Hajj, this is tamattu’. His first ‘Umrah does not mean that he was doing tamattu’, according to the majority, but the second ‘Umrah which he did and then stayed in Makkah until he does Hajj means that he is now doing tamattu’. 

Shaykh Ibn ‘Uthaymeen said: 

If the pilgrim who is doing tamattu’ goes back to his city then sets out again from his city to do Hajj, then he is doing ifraad, because of the interval between ‘Umrah and Hajj that occurred when he went back to his family. His setting out means that he is embarking on a new journey to do Hajj, so in this case his Hajj is ifraad. So he does not have to offer a sacrifice in this case, but if he does this as a trick to try to avoid having to offer a sacrifice, then he is not relieved of that obligation, because trying to use tricks to avoid doing an obligatory duty does not mean that one is relieved thereof, just as trying to use tricks to do something haraam does not make it permissible.  

Fataawa Arkaan al-Islam, p. 524.