When your organization is preparing for a large ERP or related project, often involved is one or more implementation partners that will be providing a large amount of consulting services over a long term.  In order to organize the supporting team of internal resources that the vendor will need and keep costs in-check, its recommended to appoint an internal project or program manager to lead the vendor management. Not only does it makes good business sense but this person will also serve as the first point of contact for the vendor and be an advocate for the business throughout the implementation.   

Most vendors strongly encourage the business to name this role as vendors have comfort knowing they have a contact that understands the entire process.  Many companies do not have someone available that can dedicate the time it takes to fill this role, and leaving it vacant or without the proper dedicated resource is not advised.  An independent consultant is often used to fill this role.