We would like to be able to change the REST name of web services in Portal and AGOL.
There is documentation indicating this could be possible but after testing it with ESRI analyst, renaming the REST name, at first glance, does not seem possible. The analyst is currently seeking additional resource to look into this issue andto be sure that renaming service is not supported.
The documentation is:
Rename Service with ArcGIS REST API (doesn't work)
How To: Change the name of a feature service (changes only feature layer)
Update Definition (Feature Service)—ArcGIS REST API: Services Directory | ArcGIS for Developers (payload doesn't stick)
This idea change is related to the following post: