Hi Bob. "Having trouble" doesn't tell us anything. Show us what you've got.

Sorry.  Frustration showing....
I have the data being entered in to Table one named, TradeShowTravelDataT  that I need to get in to auto populate into Table Two, TradeShowExpenseT.  I want it to be able to INSERT OR UPDATE if the data was already inserted into table two.
The Tradeshow ExpenseT will also have entries made directly for things unrelated to travel expenses.
What I need is a safe way to UPDATE the data if the record already exists, for let's say the price changed for the airfaire.  and append the data if it does not, like a new entry.   I have primary keys and foreign keys set up.  

TradeShowTraveDataT             TradeShowExpenseT

TSTravelDataID  primary key    to TSTravelDateID  as foreign key
TSID                                      to  TSID  
TSTravelbookedDate                 to TSExpenseDate
TStravelExpensePaidTo             to TSExpenseTo
TSTravelBookedBy                   to TSExpenseby
TSTraveExpense                      to  TSExpenseAmount

The TradeShowExpenseT has a primary key as well as an auto number

I wouldn't use two tables to store essentially the same thing. Use one table and indicate the type of expense it is. Travel could be an option.

I didn't explain my self properly.  I'm sorry.  The travel table has 12 more fields, and the ezpense table has one more what I listed is just where they overlapped.
Thanks for your replies however.

I would still put that data in a single table. Its OK if there are some fields that one "type" needs that the other doesn't. It would be like having separate order tables for computers and televisions. They're both products that you sell. Sure, there may be SOME different fields for each, but a lot of overlap.

Late to the party here but watch the Too Many Tables video.
This explains how to add in data for certain types.