create new transaction code for this new transaction variant

Dear Expert,

I have created the screen variant from SHD0, and it works. I can see the screen that I want, with only the production version field is unlocked, others are locked.

but the problem is how to create new t-code? so that the t-code MD12 itself is not influenced. do we able to create the new t-code from SHD0?

if can, how?

I realise when I assigned the screen variant to the new transaction variant , this changes is cross client.

To go back to original screen of MD12 just delete the assigned screen variant right??

please advice,

Thanks

Pauline