{
	"@odata.context": "https://portal.xpertdoc.com/odata4/v6/$metadata#ContentLibraryFiles/$entity",
	"ContentLibraryFileId": "00000000-0000-0000-0000-000000000000",
	"ContentLibraryId": "00000000-0000-0000-0000-000000000000",
	"ContentMetadataFormId": null,
	"ParentContentLibraryFolderId": null,
	"LinkedContentLibraryFileId": null,
	"FileType": "File",
	"Name": "New Name",
	"Metadata": null,
	"SequenceNumber": 0,
	"CreatedByUserProfileId": "00000000-0000-0000-0000-000000000000",
	"CreatedDate": "2016-01-01T00:00:00.0000000Z",
	"ModifiedByUserProfileId": "00000000-0000-0000-0000-000000000000",
	"ModifiedDate": "2016-01-01T00:00:00.0000000Z",
	"Timestamp": "AAAAAAAEqeY="
}

var contentLibraryFile = portalContext.ContentLibraryFiles.Where(clf => clf.ContentLibraryFileId == Guid.Parse("00000000-0000-0000-0000-000000000000")).FirstOrDefault();

contentLibraryFile.Name = "New Name";
contentLibraryFile.ValueToChange = value;
	
portalContext.UpdateObject(contentLibraryFile);
portalContext.SaveChanges();