Go to General System Administration -> General System Parameters -> Location File Maintenance (KC0003) -> Do a Look Up or Location/Dept.
Here you can change the Address, Ship To Address, Phone Number, etc. -> Click OK to save any changes when finished.
NOTE: Making the change does not change existing Purchase Orders, Requisitions, Invoice, etc. only changes it for new one's that are entered.
If you want to change it in KeyNet, then go to FIS System Admin –> Control File Maintenance -> Financial System Parameters –> FIS KeyNet Control Parameters