Bought a Roku TV (55" TCL Roku TV) at a garage sale & has old owners Roku account on it.
How do I change that? Can it be done without loosing everything?
No, you will have to do a factory reset and start roku account of your own, you'll have to add the apps back and sign in with your credentials. IF you have acces to the settings via the remote:
home> settings> system> advanced system settings> factory reset> follow prompts.
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