Using @josecgomez 's method will require a block of custom code to be written in your BPM but is arguable the cleanest method to force a refresh. Let’s start there.
In your BPM, instead of invoking a BO method, we will use a custom code block. In that block, we will define our service that we want to go after and we will call the GetByID method
using(Erp.Contracts.QuoteSvcContract quoteSvc = Ice.Assemblies.ServiceRenderer.GetService<Erp.Contracts.QuoteSvcContract>(Db))
{
QuoteTableset QuoteDs = quoteSvc.GetByID(<"YourQuoteNumVariable">);
this.dsHolder.Attach(QuoteDs);
}