Changing an adobe account

To add to what 'selondon' already mentioned, photos imported into Lightroom can only be accessed with that specific Adobe account. 

If you want to use another email address to sign into Lightroom, but you want to keep the existing images, you can simply update the email address your Adobe account uses:

1. go to: https://account.adobe.com/ and sign in

2. click on Change Email, and update your Adobe account to use the email address you prefer.

3. Sign out and sign back into Lightroom to ensure you can still access your images.

If you have a subscription with Cloud Storage then no, although there is a kind of work around for transferring between accounts. 

Not quite sure how it works if you have a free account but assume the photos are linked to the original account.