Changing the auto-generated emails from SNOW

I work for a huge corporation and my regional service desk received a ticket a month ago where the user is also working in SNOW , handling legal tickets. The legal team has changed their telephone number and they need this to reflect in the auto-generated emails from SNOW.

So far we are stumped however.

1. the email sent out does not originate from @service-now.com , they seem to come from a mailbox that exists in our AD

2. I have checked Exchange Admin Center for this mailbox and the signature cannot be edited from there

3. I gave myself access to the mailbox and logged on to it via Outlook Web Access; there is no signature set there, no automatic replies.

4. I sent the ticket to our  global SNOW ITSM team, they sent the ticket to the global email team...

5. ... who sent it back to my service desk with a worknote saying that the signature is likely made in outlook.

I fail to see how SNOW can fetch a signature from Outlook, since Outlook is a client. Outlook signatures are set locally , e.g if you send an email from Outlook Web Access you won't have the same signature as in your local hard client. These auto emails also have the "Ref:xxxxxxxxxxxxxxx" in the email body which again gives credence to the theory that this cannot possibly be sent out from a hard client(?!).

Disregarding the fact that the legal team should have documentation on who set up their signature and how they did it, it seems our IT org does not have documentation on this either. 😕

Can anyone point me in the right direction?

Thanks 🙂

PS. i know this is not a PRB mgmt question, however it is a problem 😜