I was about to post about it.

You can get anywhere in the universe in the subjective time (called proper time in Relativity) you want, just by adjusting how close to the speed of light your ship travels.

Let's say your ship travels at 95% the speed of light. Then it will take you about 1 year (proper time) to arrive to Alpha Centauri, but it is still 4.37 lightyears appart from Earth, so 4.37 years have passed when you arrive there.

Now, you decide you want to take half a year to get back to Earth. You'll have to accelerate to 99% the speed of light in order to do so.

When you arrive to Earth, you've experienced that a year has passed for the Earth-Alpha Centauri trip at 95% c, and half a year has passed for the Alpha Centauri-Earth trip at 99% c. You are 1.5 years older than when you started, but almost 9 years (4.37 + 4.37) have passed for people on Earth since you left.