In Umrat-ut-Tamatu, the second obligation is tawaf. If a pilgrim deliberately abandons it, his Hajj, shall be null and void, irrespective of whether or not he was aware of the rule governing the matter. Delaying its performance could be materialized in a way that it would no longer be possible to perform it, as it would be time for the devotional stay in Arafat. Thus, the Umrah will be invalid. Apparently, the ihram will also be invalidated. [And as a rectifying measure], reverting to Hajj-ul-Ifraad is not sufficient, although one should do so, as a matter of precaution. In both the situations, it is obligatory to repeat the Hajj in the following year.