Setup > Customize > Accounts > Partner Roles
Partner Role Picklist Values: You can create new, edit, reorder, replace and printable view to partner role.
Partner Role Picklist Values > New
Partner Role: System Engineer
Reverse Role: Client
Add one or more picklist values and each value create own line and save.
Partner Role: System Engineer added in the partner role.
Partner Related List > New
Select Partner, Role and Save.
Partner added to the account record.