BobP - BIM
First of all, I am assuming that by a linked report, you mean a report that is called from another report when the user clicks on it.
There are a couple of ways you could do it.
1. On the linked report, set the default parameter values to the same Query that populates the parameter.
2. On the calling report, set up a new hidden parameter, and populate it with the same query that populates the parameter in the linked report. On this new hidden parameter, set the default to be the same query that populated it. Then, when the report is called, pass the new parameters!parameter.value to the report.
Hope that helps.
BobP