Yes, you can import your address using its private key to another Bitcoin wallet.
how do that? Yes, you can import your address using its private key to another Bitcoin wallet
also,
Can You change the private key?
What kind of change? I don't think you can change a private key of an address because it's fixed for that address.
If you have the private key of an address, open your Bitcoin-QT client, click Help, click Debug Window, go to Console tab, type
walletpassphrase "Your wallet passphrase" 600 to unlock your wallet for 600 seconds or 10 minutes, then press enter, then type
importprivkey your_private_key and hit enter, beware that this would take awhile as far as I know so be patient.