You are the owner of ABC Google+ page and you want to transfer the ownership to other user.
As the owner, access to your Google+ and click on Pages tab. You can get to the below screen by highlighting your cursor to Home tab (located on the left side)
Click on Manage this page.
Hold your cursor to My Business and select Settings.
Jump to Managers tab. You will see the list of Managers here. So, click on Manager box and select Transfer ownership to NEW_USER.
Press OK to transfer. The transfer will be fast and take only seconds.