Error in form 16. loss from hp shown as income?

Sir,

My client has worked in two different organisations in FY-15-16 & so in possession of two different Form 16. In one of the Form 16 in which he has given all the details to his employer, the employer bymistakely enters income from House Property instead of Loss from HP. My question is : -

1) which ITR to file 1 or 2A? Is it necessary to file ITR 2A if salary is from more than one employer.

2) Also how to rectify the error made in Form 16? can i claim loss from HP in my ITR & will there be any problem (even if i have to file itr1)?

Thanks & Regards