Tender recipient can only be determined by the buyer who can decide which supplier account is able to work with them, this is business decision from the buyer. Therefore, supplier have to contact buyer to change the recipient of any invitation email.

To change the recipient of any invitation email, a buyer need to check whether this supplier user is Public or Private in their realm by following Customer Services & Support Knowledge - How do I know if a supplier is Private or Public?

After that, the buyer needs to follow Customer Services & Support Knowledge - How do I update a supplier's email address/telephone number in my realm? to update supplier's email address for receiving invitations.

If you are a buyer with Application.AOD.EnableAdditionalSupplierUserDataSync and Application.AOD.EnableAutoApproveSupplierUserOnDataSync parameters enabled in your realm, the supplier will need to update the email address/ telephone number in his/her account and it will be reflected in your realm. For more information see, What happens when a supplier organization creates a new Ariba Commerce Cloud user?

Strategic Sourcing > Sourcing Events
Supplier Information & Performance Management > SIPM Registration/Login