How to get Guid ID from localContext.OrganizationService.Update(entity)?

Hi,

I have a plugin with following codes:

Guid entityId = Guid.Empty;

….. entity has been created here

entityId = localContext.OrganizationService.Create(entity);   //this one is compiled OK, it returns the Guid of the entity,        

However, I got compile error if I use the following code:

entityId = localContext.OrganizationService.Update(entity); //the compile time error for this line code shows "Cannot implicitly convert type 'void' to System.Guid, "

my question:

Is there anyway to fix this compile time error to get the entity Guid ID above?

Thanks again

Peter,