Halliday & Matthiessen (2014: 239):
With a Client, the ‘service’ may likewise be construed as the Goal, especially a Goal of the ‘created’ as distinct from the ‘transformed’ type, one that is brought into being by the process – the ‘creative’ type of ‘transitive material’ clause; e.g. a picture, this house in he painted John a picture, built Mary a house. But it is really the process that constitutes the service; hence a Client may also appear in an ‘intransitive’ clause – one that has no Goal, but has either Process + Scope, e.g. played Mary a tune, or else Process only, as in play for me. These last cannot appear without for (play me); in order to show that they are Client it is necessary to add a Scope element in final position (play for me – play a tune for me – play me a tune).