Yes, you can totally do that. National Eligibility cum Entrance Test or NEET is very liberal with this fact and is as rigid as the Joint Entrance Examination or JEE. In JEE you can only give the exam two to three times in your lifetime but there is no such clause for NEET. So you can easily attempt your class XIIth examination again from CBSE board and attempt NEET after you pass with marks good according to you.

Hope I have answered your question. All the best!