Dear student,

Now if you to got allotted any seat in josaa but you want any higher preference seat in other colleges or institutes then you can use the float option.

FLOAT -  this options means that you have accepted the seat and but you want to get any higher preference branch or higher preference college in further rounds and if you Will get them you will accept it.
Now if you used the float option then you have to pay the seat acceptance fees for that allotted seat.
Now even though you didn't get any higher preference branch in next round then still your previously allocated seat will remain with you.
So, you can get only branch at a time, and if you get cse in further round then you can accept it otherwise the ece branch will remain with you.

But you must have to pay the seat acceptance fees and upload the documents after your allotment because if you don't do this before the deadline date, then your previously alloted ece seat will be cancelled and your float option will give you no benefit

Also check out the following link to know more about the josaa counselling :-
https://engineering.careers360.com/articles/josaa/amp