Inside the current revision of the proposal for an OData Delta Query Protocol i.e. [OData Delta Query Protocol Design 2012-12-19.docx](https://www.oasis-open.org/committees/download.php/47755/OData%20Delta%20Query%20Protocol%20Design%202012-12-19.docx) please consider rewriting:
"""
Requesting Delta Links

An OData client may request that a service return delta links by including a Preference value of odata- request-deltas in the Prefer Header of the request. Services that support deltas should return a delta link, if possible for the request, but may ignore this value. Services may return delta links when this value has not been specified.
"""
into:
"""
Requesting Delta Links

Services MAY return delta links. An OData client MAY request that a service return delta links by including a Preference value of odata- request-deltas in the Prefer Header of the request. Services that support deltas SHOULD return a delta link, if possible for such a request, but MAY ignore this value. """

to ease understanding of main statements and extraction of conformance tests.