Throughout most interactions Guilty Spark has had with others, he always would introduce himself as “Greetings, I am 343 Guilty Spark, Monitor of Installation 04”, it was sort of synonymous with his character. However now that he is in the body of a Promethean Soldier (yes Spark survived Halo 3 and through a series of events, wound up on a Forerunner planet and uploaded his core into a Promethean Soldiers body) how exactly would this interaction carry on, if 343 decided to bring Guilty Spark back in a future game or during Infinites life span. Given he is no longer a monitor and that Installation 04 is destroyed, he can’t really keep that title anymore and I don’t think him saying “Greetings I am 343 Guilty Spark, Former Monitor of Installations 04 that is not traped in a Promethean Soldiers body”.
Whatever it is, he’d be interrupted with Chief’s combat knife thrown into his face 
Spoilers for Point of Light bellow:
I guess now he’s “Spark, caretaker of Bastion”.
Perhaps he needs Master Chief to help him find a new monitor body because he find the amiger body limiting and with a new monitor body he can do a lot more. Perhaps this could mean he can help Chief and Arby when they go to the Maethrillian or the Broken circle.
I think it would definitely be a lot snarkier
By being shot by a spartan laser before getting a word out.
I’ve thought about this a lot and I honestly think he would introduce himself along the lines of “I am Spark. But perhaps you remember me as 343 Guilty Spark”. Chief would keep his gun up, aiming at Spark’s armiger body.
I think this because it’s likely Chief remembers everything 343 Guilty Spark did, and even if Spark regrets it all, it still happened and he did what he did.
Their reunion would definitely be a rocky one, that’s for sure.