Add note about sponsorship cancellation when switching enterprise plan (#61319)

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
Co-authored-by: Laura Coursen <lecoursen@github.com>

Author: 3 people

content/organizations/managing-organization-settings/upgrading-to-the-github-customer-agreement.md

@@ -24,6 +24,9 @@ You can upgrade to the {% data variables.product.company_short %} Customer Agree
 1. In the text field, type the name of the company, non-profit, or group that owns the organization account. This is the entity that will enter into an agreement with {% data variables.product.prodname_dotcom %}.
 1. To agree to the {% data variables.product.company_short %} Customer Agreement on behalf of your entity, click **Accept terms**.
 
+> [!NOTE]
+> When you upgrade or switch your enterprise plan, your existing payment method is not carried forward. If you do not add a new payment method before your next billing cycle, active paid subscriptions—including {% data variables.product.prodname_sponsors %} sponsorships—are automatically cancelled. To avoid disruption, add a payment method immediately after upgrading.
+
 ## Further reading
 
 * [AUTOTITLE](/free-pro-team@latest/site-policy/github-terms/github-terms-of-service)