Internal Job Posting - can the current manager hold me back and not let go in the new department even though I'm selected?

I am working in an IT company for a year now , initially training for period of 6 months and then currently project for period of 6 months.
I was told to have the designation of MS D365 technical consultant but later given the position of MS D365 CRM Customer solution associate. I was not happy with the designation and was trapped in words initially in the project.

I had an opportunity to apply for internal job posting for automation testing, I applied and also selected for that Position

My question is, can the current manager hold me back and not let go in the new department even though I'm selected?
What if they trap me again and not let me go in the selected department?
What action should be taken in such case?
Kindly suggest

Hi,

These are company specific issues. Even though you got selected, consent of your Reporting Authority will be taken into consideration. Also other factors like who will replace your current responsibility etc. Finally it is purely at the discretion of your Management and you can't demand as a matter of right. However the only weapon you have is resignation. If not happy with current role and responsibility look for a new job as per your desire and move on!