Can Umrah be done, having missed some days of fasting?

Every Muslim should be keen to visit the Sacred House of Allah in Makkah and perform ‘Umrah. This visit revives one’s faith, enhances iman, and brings about closeness to Allah and His Messenger (peace and blessings be upon him). According to some scholars, `Umrah is obligatory on those who can afford it. The word `Umrah means visiting or attending. `Umrah is an act of worship. Allah Almighty says: (Perform the Hajj and `Umrah for Allah…) (Al-Baqarah 2:196). The Prophet (peace and blessings be upon him) is reported to have performed the `Umrah after the treaty of al-Hudaybiyah and he explained to people how to do it. However, going to ‘Umrah does not stipulate that one must make up for the days missed in Ramadan. ‘Umrah can be performed while one still needs to make up for those days.
Having stated that, a muslim should do best to fast those days as early as possible. It is a kind of debt to Allah and it must be paid back. All what is needed in every religious rite is the full sincerity to Allah as He only accepts good deeds of those who are sincere.