Guest Refund

[Anne99]

My guests would like to depart (11days) earlier.   In the meantime I have rebooked 7 days out of 11.  The guests have sent me a change to their reservation but the refund they will receive is minimal.  I would like to change this refund.  Do I decline their request and refund them under the Resolution Centre - partial reimbursement?  Will I be penalised in anyway and does the partial reimbursement include any extra service fees?  Thank you