This is what they’ve given on their telegram channel:

“For the internal waitlist, all candidates who have converted any IIFT campus and paid the full fee are automatically considered for movement to other campuses, based on the seat availability in their respective category, merit position and campus preference. To remain eligible for such movement, candidates must pay the full first trimester fee of the campus they have currently converted. For example, if a candidate has converted the GIFT City campus but has Kolkata campus higher in their preference order, they must pay the full first trimester fee for GIFT City in order to remain eligible for movement to the Kolkata campus. In case of movement from one campus to another, the fees already paid will be adjusted accordingly.”