Basement shower drain

I saw almost all the shower drains are located at the center of the base. It is a mandatory requirement or is just a nice to be? I have an existing floor drain and want to use it as the shower drain. If I use it as is it will not at the center of the shower base. I hope I don't need to break the concrete to relocate it.

You have to break concrete anyway.
A floor drain does not a shower drain make.

Any mudset, or any shower pan will need to have the floor broken. Whether you decide to relocate depends on where the molded pan drain location is, or where you want the drain on a mud set.

The drain can go anywhere you want it. In the center is the usual location because that makes the slope in the floor "even" in all directions. You would have an unusual residential floor drain it yours met the requirements for a shower drain.