The honest answer is the same as for any negative mark: you cannot simply erase a repossession that is accurate and within its reporting window. What you can do is correct any errors in how it is reported, resolve the balance that often follows a repossession, and -- once that is handled -- ask the lender for a courtesy adjustment. A repossession actually creates more than usual to check, because the process has legal steps that lenders sometimes get wrong, and those mistakes are disputable.
Dispute errors in the entry (free)
Start by pulling all three reports from AnnualCreditReport.com and reading the auto-loan tradeline closely. Under the Fair Credit Reporting Act, the credit bureaus must investigate disputes, and anything they cannot verify must be corrected or removed; the CFPB explains how at consumerfinance.gov. Repossession entries carry several commonly disputable details: a wrong balance or deficiency amount, a misreported date of first delinquency, a repossession listed as "voluntary" when it was not (or the reverse), a duplicate listing, or an entry still showing after the seven-year window should have closed. There is also a substantive angle unique to repossessions -- under UCC Article 9, the lender generally must sell the car in a "commercially reasonable" manner and send you proper notices. If it failed to do so, that can affect the deficiency it is allowed to report, which is worth raising. Submit disputes in writing and keep copies; the bureau generally has 30 days to respond.
An accurate repossession ages off in about seven years
When the repossession is reported correctly, time removes it. Most negative items, repossessions included, can stay on your report for roughly seven years from the date of the original delinquency that led to the repossession -- not from the date the car was taken or sold, and not from the date you later pay any remaining balance. Paying the deficiency does not restart that clock, and as the item ages its weight on your score generally lessens well before it drops off. The FTC warns at consumer.ftc.gov that no company can legally remove an accurate, timely repossession, so treat "guaranteed deletion" offers as a red flag.
Handle the deficiency, then ask for goodwill
A repossession usually leaves a deficiency balance: the car sells for less than you owed, and the gap remains as an unsecured debt the lender can pursue or sell to a collector. Resolving it does not delete the repossession, but it matters for two reasons -- an unpaid balance keeps generating collection activity, and a paid or settled status reads better than an open one. Because the deficiency is unsecured, it can sometimes be settled for less than the full amount; get any agreement in writing, and remember a forgiven balance over $600 may be reported as taxable income on a Form 1099-C (see irs.gov). Once the account is paid or settled, a short, factual goodwill letter can ask the lender to remove or soften the mark as a courtesy -- no guarantee, but free to try. As always, skip "credit repair" companies charging upfront fees; the CFPB notes they cannot do anything you cannot do yourself for free.