No, Texas does not require handgun registration.
No, Missouri does not require handgun registration.
No. The state of Kentucky does not require handgun registration.
If you are asking how to change registration of a handgun in Arizona, the answer is, you don't. There is no such thing as registration. Arizona does not require it, and there is no national registration.
the state of Missouri does not require handgun registration.
You don't. Kansas doesn't require registration.
Kansas does not require handgun registration, so the answer is, you can't register it.
It depends on where you are. There is no national handgun registration and only a handful of states require it.
It depends on where you are. In the U.S. only a few states require registration and there is no federal registration.
You don't. Texas doesn't require registration.
Where are you? Most U.S. states do not require registration.
Go to the nearest police station. Actually, the answer is, you don't. The state of Florida does not require handgun registration.