{
	"@odata.context": "http://portal.xpertdoc.com/odata4/v5/$metadata#TemplateLibraries/$entity",
	"TemplateLibraryId": "00000000-0000-0000-0000-000000000000",
	"BatchGroupId": null,
	"Name": "Library Name",
	"Description": null,
	"ExecutionTimeoutInMillis": 30000,
	"EnableTemplateExecutionArchiving": false,
	"TemplateExecutionHistoryCount": 0,
	"TemplateExecutionHistoryTimeInMillis": 0,
	"Metadata": null,
	"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": "AAAAAAAAOGQ="
}

var templateLibrary = portalContext.TemplateLibraries.Where(tl => tl.TemplateLibraryId == Guid.Parse("00000000-0000-0000-0000-000000000000")).FirstOrDefault();		

templateLibrary.Name = "New Name";
templateLibrary.ValueToChange = value;

portalContext.UpdateObject(templateLibrary);
portalContext.SaveChanges();