Is there a way to rename a Future / Spare segment name in the GL Key FF

Summary:

On Implementation we created a COA with 2 segments for future use.

The future has now arrived and we want to use one of these segments but can see no way of re-naming it to something meaningful.

Content (required):

I think this is intended functionality but would like confirmation and also whether there is any workaround as I would imagine this is a common scenario 

Version (include the version you are using, if applicable):

Cloud ERP R13 21 D

Code Snippet (add any code snippets that support your topic, if applicable):