The baseurl directive in your .repo files in the /etc/yum.repos.d directory often contains the $releasever (Release Server) variable, something like this.

~]# grep -i baseurl /etc/yum.repos.d/redhat.repo 
baseurl = https://satellite.example.com/pulp/content/rhel7/content/dist/rhel/server/7/$releasever/$basearch/optional/os

Sometimes, the $releasever variable in derived from the distroverpkg variable in the /etc/yum.conf file, something like this.

~]$ cat /etc/yum.conf
distroverpkg=8.9

The subscription-manager release command can be used to determine if the release has been set by Subscription Manager. Often, it is not set.

~]# subscription-manager release
Release not set

The subscription-manager release --list command can be used to list the available releases.

~]# subscription-manager release --list
+-------------------------------------------+
          Available Releases
+-------------------------------------------+
7Server
8.9

The subscription-manager release --set=<release> command can be used to set Subscription Manager to a specific release.

subscription-manager release --set=7Server

This should update /etc/yum.repos.d/redhat.repo immediately. Notice now basesurl has 7Server instead of $releasever.

~]# grep -i baseurl /etc/yum.repos.d/redhat.repo 
baseurl = https://satellite.example.com/pulp/content/rhel7/content/dist/rhel/server/7/7Server/$basearch/optional/os

The subscription-manager release --unset command can be used to unset the Release.

~]# subscription-manager release --unset
Release preference has been unset

This should update /etc/yum.repos.d/redhat.repo immediately. Notice now basesurl has $releasever instead of 7Server.

~]# grep -i baseurl /etc/yum.repos.d/redhat.repo 
baseurl = https://satellite.example.com/pulp/content/rhel7/content/dist/rhel/server/7/$releasever/$basearch/optional/os