Transaction --> Incomplete <button>

I have made a Transaction (in Receivables) and completed it

Applied a receipt to the transaction

due to entry error, i need to update the Transaction

so, i un-applied the Transaction from Receipt

Note: the accounting for Transaction and Receipt have not been generated

Still the Transaction --> Incomplete <button> is showing as disablled,

Kindly share, how to make the invoice incomplete?

Arfeen Mushtaq