Yes, a Pro subscription can move to another 1SE account. How depends on where you bought it.
Bought through the App Store or Google Play
It belongs to the Apple ID or Google account that paid for it, and Pro applies to whichever 1SE account is signed in on that device. On that device:
Tap the Settings icon > Account > Sign Out.
Sign in with the 1SE account you'd like Pro on.
Tap Settings > Restore Purchases.
Pro now applies to that account. If it doesn't, make sure the device is still signed in to the store account that paid.
Bought on our website
A subscription from me.1se.co stays with the 1SE account signed in when you paid. You can't move that one yourself, but we can: message us from the app's Settings > Contact Support with the email it's on now and the one to move it to.
Moving to a new phone is different—see how billing works when you move between iOS and Android.