When arranging a pilgrimage, the participant is asked to declare their objective before the outset of the journey.
Muhammad decreed that Umrah and Hajj can be combined, i.e.: starting a pilgrimage with the intention of participating in both events.
While doing a pilgrimage, whether minor or major, the Muslim needs to adhere to some very strict dress codes that also includes some other rules (Arabic: Ihram).
In pre-Islamic Arabia, if one would go to the minor pilgrimage a short period before the major one would commence, he was forbidden to go out of the dress code if he intended to follow it up with a Major pilgrimage.
This rule was abrogated by Muhammad, who said it was permissible to leave the state of Ihram if one intended to attend Hajj.