Modifying Filters

I know this has been covered before, but the new search engine isn’t working. So, for a report, the user enters a filter for a field. I want to copy what the user enters into a variable, and then append an extra condition, and apply the new condition to a variable in another Record variable. Any help would be greatly appreciated.

ItemDateFilter := Item.GETFILTER(“Date Filter”); (ItemDateFilter is a variable of type text)

Use funcion Copyfilter, or Copyfilters if it’s same record