Hello dear..

Yes, You can do so in 2017, cap round 2/3. kindly refer to following website.

State Common Entrance Test Cell, Government of Maharashtra ::..

refer page 23 point 9 (3). which states that

9(3) Conduct of CAP Round-II and III.- (a) The seats available for CAP Round II and III shall be published on the website. The Candidates are allowed to fill in or edit the already filled online option form. The seats to be allotted during these rounds shall be subject to following conditions.- (i) Before start of these rounds, the Candidates can change their seat acceptance option from Slide or Float to Freeze or viceversa by submitting an application at Admission Reporting Centre (ARC) where he has confirmed his admission by paying the seat acceptance Fee

Best of luck..