Travel Card for terminated employee

We have implemented Travel Card functionality of Oracle in R12 and wondering how would we deal in the below situations:

- if an employee is terminated and his or her travel card transactions come in the bank file

- If the travel card transactions are uploaded and the employee leaves without submitting an expense report

- If the employee has created the travel card expense report and the expenses is not yet approved and he/she leaves

- If the employee leaves and the expense is approved but the invoice is not yet created

Thanks

Naushad