Can I change my branch from IIIT Lucknow to IIIT Allahabad?

The change of branch is achievable while the change of campus is not. The following example may clear your idea about the branch change between the institute. 

Branch Change:

As of now, IIIT Lucknow only has two branches. If you are enrolled in ECE in IIIT Allahabad, then you can try changing it to other branches in IIIT Allahabad.

That means, if you are in IIIT Lucknow, then changing the branch to anything offered in IIIT Allahabad is not possible.

IIIT Lucknow:

• Yet, if you consider the facilities that you can avail at IIIT Lucknow, then the choice can be worth it. The students of IIIT Lucknow can be on the list same as IIIT Allahabad, or sometimes even higher.
• The campus may take some time to be developed properly. Apart from that, it certainly is a good choice, provided the circumstances and the support received from the seniors.
• IIIT Lucknow is one of the major 20 IIIT institutes in India, that basically was established under public-private partnership mode.
• Graduates from this institute get their placement in top-notch companies such as Google, Amazon, Microsoft, Collegedunia, LinkedIn, Nykaa, Samsung, Paytm, etc.

Also, students from either of the two institutes, namely, IIITL or IIITA are not treated any differently.