Currency Exchange for petty cash account?

Hi,

We got an issue here:

We have CNY(Chinese Yuan) and USD account here, but we sometime need HKD and AUD. So we will exchange the CNY into HKD from bank. So that is Credit the CNY bank account, and Debit the HKD petty cash account.

May I ask do SAP have standard process for this process? Debit HKD petty cash account, and Credit CNY bank account. And what T-code it is?

Thx very much~!