Transition from one course to another is permitted by some of the college/University. But transiting from BCA to BCOM after 1st year may not be possible as the 1st year course of BCA is completely different from BCOM. In engineering, trades can be changed after 1 year, because the curriculum for the 1st year of BTech is the same for all the trades. But in case of BCA & BCOM this correlation isn't present. As a result, I would recommend you to contact your institute for the procedure, but this in most cases, will not be possible. Although, If you wish you can enquire at least.

For more information regarding the BCA visit:

https://www.careers360.com/courses/bca-bachelor-of-computer-applications

For more information regarding BCOM visit:

https://www.careers360.com/courses/b-com-bachelor-of-commerce

I hope this helps. Wish you a great day!