I don't see change customer button on the project record, I went to SuiteAnswer looking to find something I found out that, that button appear or not appear is based on how you created a contact for that customer/project, but when I went on the customer and project record, there is no contact created. The User would like to know why the button Change Customer appears only on recently created projects, but then after a while the button no longer appears. Solution 1. On the Project Record > Relationship > Contacts If the Contact is made out from an Existing Contact (added via the Contact Drop down), the Change Customer button will be still available since the contact record was not created via the current project making it not a source record of the project. 2. But if the Contact added on Relationship was done via the New Contact button, the Change Customer button will now not be available since the contact was created out from the current Project making it a source record out from the project.

If I remember it right, something is wrong with this article. We encountered the same before. I just could remember it now. By any chance though, don't you have transactions associated with that project yet?