I would use a Delete query to clear the data. An Append query to add the data.
Without knowing more about how the form works, I am not sure where to place the code.
For exmample, if you have a pop-up for that display the single record then:
1) open the form passing an open args witht he primary key for the desired record
2) In the On Load event run queries to clear the tmp table and append the desired record using the value passed in the OpenArg
3) requery the form.
or maybe
1) open the form
2) In the On Load event run queries to clear the tmp table and append the desired record using a form reference to get the the primary key for the desired record.
3) requery the form.