when you remove an iphone from account how do you retrieve its data to transfer to a new phone

Removing the phone shouldn't affect the iCloud data. Try using the iCloud.com using a computer browser method in the article below.

Archive or make copies of your iCloud data.    

If the phone that was removed was backed up to the cloud, you will be able to select to restore the new phone from that backup during the initial setup of the new phone.