An accepted offer amount can't be edited in the app.
If the amount needs to change (for example, adding a courier cost), send us your deal number and the new total. We can amend it manually after a quick confirmation with the other party.
You can also settle any difference with the other party directly. Please note that anything paid outside Bike Hub Pay is not covered by buyer or seller protection, so keeping the full amount inside the deal is the safest option.