How do you deal with customer returns/exchanges

[Nigel Titley <..hidden..>]

Folks,

How do you deal with customer returns/exchanges? We have a customer who
wants to return item A and replace it with item B. We can raise an
invoice for item B but how do we get item A back into inventory and
raise a credit for it?

Thanks for any advice, including "it's on page xxx of the manual"

Nigel