Thanks for bringing up Romans 6 Frank. It is really shameless how the JW use this scripture to nullify the work that Christ did on the cross.
NWT
4 Therefore we were buried with him through our baptism into his death, in order that, just as Christ was raised up from the dead through the glory of the Father, we also should likewise walk in a newness of life. 5 For if we have become united with him in the likeness of his death, we shall certainly also be [united with him in the likeness] of his resurrection; 6 because we know that our old personality was impaled with [him], that our sinful body might be made inactive, that we should no longer go on being slaves to sin. 7 For he who has died has been acquitted from [his] sin.8 Moreover, if we have died with Christ, we believe that we shall also live with him. 9 For we know that Christ, now that he has been raised up from the dead, dies no more; death is master over him no more. 10 For [the death] that he died, he died with reference to sin once for all time; but [the life] that he lives, he lives with reference to God. 11 Likewise also YOU: reckon yourselves to be dead indeed with reference to sin but living with reference to God by Christ Jesus.
In order to understand these passages, a person must understand the atonement of Jesus dying in our place. Galatians 2: 20 says:
I am crucified with Christ: nevertheless I live; yet not I, but Christ liveth in me: and the life which I now live in the flesh I live by the faith of the Son of God, who loved me, and gave himself for me.
Notice how when a person is born again something in man dies and Someone replaces it. The born again believer is totally unique. A brand new, never-before-seen creature in the universe made its appearance with the first born again believer. 2 Corinthians 5:17 "Therefore if any man be in Christ, he is a new creature"
So when a persons places his trust in Jesus Christ and no other, according to the legal stipulations born out in the New Covenant, (which JW's personally reject at each Memorial) that person receives Something inside of him that cannot sin, the Spirit of God. The flesh can still sin, but we are freed from the overpowering vice-grip of sin. I can personally testify that it is a very welcome release. The KJV calls this "freed from sin".
The NWT uses the term "acquitted" because of it's legal connotations to promote the idea that a person can atone for their own sin simply by dying. Also notice the addition of the word [His] sin, instead of the generic "Sin".
Of course this is a ridiculous heretical teaching because if true, Christ died for nothing.
We must never forget to bring up Hebrews 9: 27 when talking to a witness:
...it is appointed unto men once to die, but after this the judgment:
KJV
Therefore we are buried with him by baptism into death: that like as Christ was raised up from the dead by the glory of the Father, even so we also should walk in newness of life.
5 For if we have been planted together in the likeness of his death, we shall be also in the likeness of his resurrection:
6 Knowing this, that our old man is crucified with him, that the body of sin might be destroyed, that henceforth we should not serve sin.
7 For he that is dead is freed from sin.8 Now if we be dead with Christ, we believe that we shall also live with him:
9 Knowing that Christ being raised from the dead dieth no more; death hath no more dominion over him.
10 For in that he died, he died unto sin once: but in that he liveth, he liveth unto God.
11 Likewise reckon ye also yourselves to be dead indeed unto sin, but alive unto God through Jesus Christ our Lord.