thank you all a lot

so tell me if i'm right.....I play the lets say 9th fret of third string with my third finger at the same time holding the 7th fret of third string with my second finger to play the E note

then I let go of my third finger leaving only second finger on the 7th fret to play the D note and push the string upward to make it sound exactly like the E note?

please forgive me for so much crap here... :p hehe