Restrictions Code

I have updated my iphone 6 to an 11 pro. All is good on my new phone. I am now trying to wipe content clean on the iphone 6 to send back to verizon. I had already disabled find my phone on the iphone 6. Then I went into my name and removed icloud & itunes. Then went into settings,general,reset, erase all content and settings, but it asks me for the restrictions code(which I tried all that I can think of) and I can't remember. I have viewed all the forum answers on restriction code but If i connect to a computer and go through itunes or force a reset and will this ruin my info on the iphone 11 pro? Im just confused how to not ruin stuff my phone11 (my original passcode, not restrictions passcode). What should I do next on my iphone 6?