Can the original creditor negotiate

It depends on the creditor. Some creditors will say they can no longer deal with the account because it has gone to collections (acct. usually sold off), but I have heard of the odd instance where a creditor would work out a settlement and agree to notify the collection agency that it had been satisfied. The main thing in that situation is to get the creditor to give you something in writing to say the debt has been settled/paid and no further amount is owing.

Otherwise, you run the risk of the collection agency continuing to try and collect, as some of them are really scummy.

Regardless of whether you deal with a collection agency or creditor for a debt, ALWAYS get things in writing, so you have proof of the terms and proof that the debt has been satisfied. You never know when you may need this, especially in instances where the debt has not been updated on your credit reports and still shows as owing.