As part of SSO implementation, we have created requested the creation of a domain on our UAT instance. This was requested last week but it is still pending. My expectation is that this should only take a couple of days but it is already a week. Can you please advise?
I suggest you open a support ticket with salesforce to know the status of the domain registration.Salesforce Admin or developer won't have control on the domain registration process- https://help.salesforce.com/support