SARPs = Standards And Recommended Practices.
Standards are contained in the various Annexes.
Recommended Practices are contained in the various Documents.
Neither the ICAO Annexes nor the ICAO Documents have any specific legal status of their own.
If a State cannot fully comply with an Annex, it must file a difference with ICAO and should notify it in the AIP. States base their aviation regulations on the Annexes, which is the way they achieve legal status.
Whether or not a State can fully comply with a Document, it must detail the way it addresses the particular Document in the AIP. This is a difficulty with Documents such as Pans-Ops, for example, because the only way you find out about any differences applied by a State is to firstly know the contents of the Document and read the full implementation of it in the AIP. Some States will actually mention any differences between their implementation and the relevant item in the ICAO Document.
Hope this helps.