@Walter Basile Thank you for reaching out to us, As I understand you are trying to delete a tenant, during this process facing issues on this page "Get permission to delete Azure resources".
I tried at my end, by going to this page and make changes (like toggle yes/no) gave me option to save, i assume you might have tried it.
Would appreciate if we can offline to troubleshoot this issue in detailed and get this issue resolved as it would help other community members facing similar issue.
Please send me an email to 'AzCommunity@microsoft.com' with Sub - Attn: Givary and following details in the email body:
Link to this thread/post
We can connect offline and discuss further on this.