I want to put my old Apple ID back on my iPhone but it's been used already. Is there anyway that I can put it back on my phone?

I want to put my old Apple ID back on my iPhone but it's been used already. Is there anyway that I can put it back on my phone?

Log out whatever account it's got on it at present and log in to your original one.

You can have multiple devices - phones, tablets, computers - all on the same Apple ID.

There's a 10 device limit for an Apple ID. So this shouldn't be an issue.