Forms :: Pass Value From Form To Calling Form

I have Form A that is bound to tbl_Member (MemberId, LastName, FirstName, and some other fields).

On Form A is a combobox [cbo_Selector]. The combobox shows LastName and FirstName from tbl_Member, but when a name is selected, it returns the member's ID to Form A and causes that member's record to show in Form A (along with other data pertinent to the member). This works fine until I type a name into the combobox that does not exist in the underlying table.

I use the NotInList event of the combobox to pop up another form (Form B) in the DataEntry mode. Form B is bound to the same table as Form A. I enter the LastName, FirstName, and exit Form B. What I am trying to do is to have Form B pass back the new MemberId to Form A and specifically to add that record's data to the combobox on Form A.

I have tried several things to accomplish this. When Form B updates, the table has the new member added, but when I try to requery Form A or the combobox, I get errors. how do I communicate to the combobox in Form A the information from the newly added record?