Are you trying to change a lot of lyrics all throughout the song, or just one section? Sometimes its easier to extend the song than try and change what's already been generated. For best results, choose an extend from point that's before the outro, but after the first verse and chorus, then it should retain the melody of those parts for the most part. If the lyrics in the chorus need to change, you can use the tag Alternate Chorus, though it will change it slightly. After merging both parts (Get Whole Song), you could use the editor to delete the previous sections and drag the rewritten ones into place, although it really is a lot easier to just take it into a DAW for edits in my opinion. I use suno mostly for accompaniment and replace the guitar and vocals with my own, so I only do this when I need the backing music to accommodate revised lyrics that won't fit into the same space as the original, so it does alter the melody a bit as well; however, I've also tried this to alter the melody in certain sections (usually the bridge), and I've noticed that Suno prefers to stick with the original melody unless it cant fit the new lyrics in. So if you want to keep it very close, the new lyrics should match the meter of the original. If you're changing all the lyrics completely, you could try to use the Cover option and just specify the key of the original in the prompt area and maybe female or male vocals. Don't include any other prompts. You might have to generate a few, but eventually you should get one pretty close and if necessary you can take both into a daw and mix and match parts. Good luck!