Yes you can!
What you need to do is send the bill in question back to the Unknowns tab, then you need to make sure the system can't automatically apply this unwanted map next time, then apply the map you do want.
Step 1 - Add a note to the bill, noting what you don't like or want to have changed
Step 2 - Go to MORE > Show Invoice History and take a note of the Map ID that was used on that bill. (This is the map ID you want to remove from this supplier's memory).
Step 3 - From the Intray, click MORE > Re-Map Invoice. This will send it back to the Unknowns
Step 4 - Go to Admin > Suppliers ... pick the supplier in question ... > edit
At the bottom of that screen under 'Sender Details' you will see a list of email addresses & map numbers that are currently assigned to the Supplier (this happens when applying a map & you click 'Best Map')
Tick the ones that have the map number you don't want to use anymore, then click on OK.
Step 5 - You can now follow the usual steps to apply a different map or you can request a new map to be created for you.
Please note, if you are requesting a new map to be created for you via Map For Me please add a thorough note of what you want to see in the new map.