Charged off means that the company has basically decided that the debt will never be paid, and so have "charged off" the money.
Do you know the "why" behind the charge off? Did you move and they couldn't find you? Were you unemployed? Did you get a divorce?
Contact the store's credit department to find out the reason if you don't know. Also, you'll want to know the exact amount you owe. Be prepared to offer payments on a schedule that you can manage. Do NOT be intimidated - you are the one trying to make it right. Be careful about giving too much in the way of updated information without an agreement in place, because they will sic the collectors on you - agreement or no agreement.
Be polite, but ask for a "senior" credit person, even a supervisor. Speaking to someone who does not have the knowledge level that you need will only frustrate both of you. Recognize going in that you may be greeted with " you can't do this - we won't take payments " etc.. That's OK. ALWAYS write down the name of the person, date, time you are talking to them, and a couple of short notes about the conversation.

What you need:
Exact amount you owe.
Address to send your payment .
Name of person you are talking to.

Beyond this, whatever you or "they" agree to in a conversation will not hold up in a court or for your credit record. You must WRITE your plans, with a specific payment amount to be paid at a specific date each month. In the letter, state your full name and current address. You don't need to furnish a phone number, but if you do - be prepared for phone calls trying to badger you into making the full payment now. Please understand ---- once you pledge a certain payment at a certain time - you are stuck with it. IF you default by even 1 day or $1.00, they can come after you.

Make this letter brief and to the point. Make the closing paragraph a polite request --- "at the time that I complete this schedule and have a 0.00 balance on this account, I would respectfully request that you would update your information on my account with the credit bureau." Understand that this could take them up to 60 days.
You have the right to add your own comments to your credit report. You can do so when you start the payments - I'm not sure how much it will help you at that point - but certainly do so when the account is paid off.

If the company refuses to talk with you about your account, then send your letter mentioned above. If they return it with a note that says they can't do this, then make a copy for yourself and send it to the credit bureau with a letter of your own that says to add both to your report. Your letter would just say " I contacted ABC company on mm/dd/yyyy and attempted to pay my balance. Attached is their reply."

Good luck, and remember that being able to look at yourself in the mirror each morning and know that you are trying to do things the right way is the most important thing you'll ever do for yourself.