I purchased Photoshop CC, but I realized that I wanted Photoshop Elements instead. Can I add it to my plan and pay for it monthly or possibly change my plan
Photoshop Elements is not part of the Creative Cloud.
You purchase it separately as a permanent license.
If you just subscribed to CC, you can cancel it within 30 days.
If you need any help on that open a chat session with Customer Care. Contact Customer Care
Sunday 6pm—Friday 7pm PT
Chat is currently closed
If you do try to contact chat, make sure you are signed in with the Adobe ID that you used to purchase Photoshop; otherwise, you might not get through. I'm moving this post to licensing and maybe they can help.