I think, you would need the DCN number that was used in the original EFILED return.

Hello Mario.  I called Efile help line and they sent me to CRA Individual phone line, no one could be a solid answer.  

So if I use the DCN number, I won't have to enter original information from original tax return from 2023?  Just enter REFILE - new information you think??

Well, if you want to REFILE, its like if you were completing a brand new return. So you will need to fill the return completely  from scratch (if you dont have it) like if you were completing a brand new file, and then change the DCN number and REFILE. Also, I have never tried this myself, so i can not garantee you that this would work.