There are some where after you select the merchant is goes to "Enter an amount" screen. If this happens, hit the yellow key before you enter the amount

A Credit Card RETURN is the reversal of an approved and settled transaction which will post a credit amount to the customer’s credit card. Traditionally a RETURN is processed when the original transaction has already been settled when the original transaction still resides in the current batch and has not been settled, a VOID may be processed instead to nullify the charge. Use the steps below to complete a RETURN transaction.

For Debit return, you will want to First Select Debit by pressing the Down arrow and selecting debit (or tap on credit to change) before continuing with processing the return
It is important to note that for security and regulations manually entering a debit card is not allowed, debit cards must always be swiped at the point of sale. For a successful transaction, you must be a debit card accepting merchant
You must be subscribed to a Debit Host and PED is required.

When using a touchscreen you will select by using your finger and touching the options
When using a NON-touch-screen version, use the arrows to highlight and the Green ok to select your options

Note: On some Dejavoo terminals RETURN is already highlighted when you hit the yellow key and therefore you do not need to highlight this option manually.