Trending @Cognizant; Clarification on Promotion Process from PA to A

I have 23 months of experience at Cognizant. I would like to know the typical time period required for a designation change from PA (Programmer Analyst) to the next level (such as Associate or equivalent). If I have already completed the required experience, will the promotion happen automatically, or does it require manager approval? Could you please explain the procedure for a designation change and how the promotion process works?