Hi Sabica - sorry but I'll need more information in exactly what you did in the first place, for example, the word "reconcile" normally means reconciling (matching) a bank entry you have already entered in the books with a bank statement, others however will use it to mean say matching a bank statement entry against a bill.
So, I understood from what you said, that you entered an expense claim by someone (under Purchases>Expenses) and I'm assuming that, once the expense is approved, your system is set up to create a bill in favour of the employee which you have incorrectly matched/reconciled against a bank payment? So you now want to unreconcile that payment from the bill and re-explain it as a customer refund?
If this is the case then the link I gave you explains what to do, find the payment in the bank record (or explained bank statement) and delete it, this untangles it from the bill and puts it back in the bank statement to re re-explained.
If I've not understood this correctly please give more details of exactly the entries that you currently have.