Excess leave in articles

Hi, 

Can anyone please let me know what happens when form 108 is filed with excess leave.

I have a friend who has availed a leave of 80 days in excess of the permissible limit. 

Is it compulsory that the student has to serve the balance period with the same principal or can he do it with another CA?

And if he decides to serve the 80 days with the same principal, should he again file Form 102 for joining into articles?

Please clarify.