Repeating Macro Needs To Stop After Last Record

I am basically setting up a macro that will change the value for a field from "N" to "Y" for all records from a query. The macro works fine except for it does not know when to stop and gives an error message of "You can't assign a value to this object" after it has gone through all of the records and there are none left to change. The macro is set up like this:

OpenForm Action : This form is populated by the query and I set the Where condition to open records that don't already have a value of "Y".

SetValue Action : I use this to set the value of the field to "Y"

Close Action : I use this to close the form and save the changes

RunMacro Action : This is where the problem is. I use this to repeat the macro so it can go through the rest of the records that still have the field set to "N". I need to set the Condition or Repeat Expression so that it checks if all of the records have been changed. It either needs to check that all records have the field = "Y" or check that the macro is on the last record. Basically something that will cause the macro to not open itself again when there are no more records to be changed.