What do you mean?
There's no delivery/postal address stored on your My48 account:
Do you perhaps mean that you ordered a SIM and now need it delivered to a different address?
In that case you won't be able to change the delivery address after submitting the order.
You'll need to just order another SIM and specify the correct address.
If you need to contact 48 support about this then see links in my signature below.
