After you have successfully achieved PHR/SPHR certification, your role at work is going to change. It's not just because you now have initials next to your name. The preparation process taught you new things, and as the consummate professional that you are, you'll begin to seek change in your workgroup.
These changes will apply in two areas:
In your department: Depending on the size of your HR department, you may suddenly become a go-to person for input and advice. If so, consider mentoring a co-worker and coaching him down the certification path. Make it a goal for everyone in the department to become certified so that you're all speaking the same HR language. In another scenario, you may be an HR department of one. If so, I'm sure that you'll have identified areas for increased efficiencies within your workspace all throughout the exam prep process. Proper planning and staying organized will keep you from becoming overwhelmed.
Focus on one or two projects at a time, like auditing Form I-9s or researching employee benefit plans (sooner than the month before open enrollment). Create a master annual HR calendar to schedule special projects.
Companywide: Seeking change companywide can be a more of an uphill battle. Begin by making sure they understand what your new certification means. Tell the decision-makers what you studied and how you felt it could benefit the company. This conversation isn't one way either. Make sure that you're listening to the executives, managers, and supervisors to avoid being labeled an academic. Some of the concepts you have learned during your studying aren't a one-size-fits-all solution. Common ground is where the meaningful change occurs.