SMEAT

Yes, you can upgrade the allocated seat at Delhi University. The allocation is done through CSAS at DU for various courses and colleges for admission. During the registration process, you are required to indicate your preference. You can select the "Upgrade" option, which will allow an upgrade to a higher preference submitted by you. If you choose this option, your current seat assignment will be automatically canceled if a new seat is assigned to you. However, once you get an upgraded seat, you will have to "accept" the upgraded seat and complete the admission procedures. Otherwise, by default, your current seat will be considered canceled, and you may be declared to be out of the CSAS admission process.

Shortly after seat allotment, the official university website posts a list of vacant seats in any law college's LL.B. Counseling process. You have not mentioned the name of any particular law university, but in general, the counseling process is as follows:
1. The university announces the results of the law school entrance exams.
2. The scheduled date for the registration process for the counseling process is announced.
3. The registration and document verification depend on the university.
4. Allotment of seats and following the announcement of vacant seats for the next round
Therefore, if there are any vacant seats available, they will be published on the "notice" portal of the law university. If you are referring to DU LL.B. The process has yet to start, whereas for PU LL.B. It has already been conducted.