I really think we (and perhaps, you) need a clearer definition of what you're trying to do... and what rule establishes that the "requirement is met?"

If it's a one-off replacement, done once, you can do it manually -- with an editor -- far more readily than with a script, regexen and an ill-speced appear to the Monks.

So, judging that what you've shown is one sample of multiple replacements you need to do, give us the rule for replacement: what does the "following line" have to contain (and what is NOT allowed in it) to justify replacing the preceding line?

A good spec makes it easy for us to help. Posting a poor, incomplete or inaccurate spec just leads to frustration, all around.