How do I modify the amount of income that is subject to state income tax? Military until Aug and a resident of Texas

Looks like my original question was not completely posted...

I retired from the military on 1 Aug and was a Texas resident until then - I didn't pay any state income tax and there is no way to select "TX" on my military W2. On 1 Aug, I started my retirement pay and started having SC taxes withheld. TT is calculating SC taxes based on ALL my income, not just my retirement income.  How can I tell TT that only the retirement pay is taxed by SC, not the military pay?