iPhone 13 deal

Hello! I have been reading over the last few posts on this subreddit and was having a similar issue to someone else but enough where I thought making a new post was necessary. I had saw that metro now switched the iPhone 13 deal to be on them and was wondering, if I am not currently a metro user and just wanted to cancel the line with them without paying anything extra, (other than the line and the phone), is that possible? I was thinking of using it just as a backup phone and if it doesn’t blacklist itself, I would like to use it possibly with another carrier or with metro again at a later date. Their terms make it very confusing. Thanks!