The most obvious method would be simply to slide up, as in a barbershop standard. It clearly depends on the style/genre of your music, of course. One method might be to go to chord VI (moving the A up to a B natural), then moving to E Flat as if it were a V-I progression in E Flat.
To modulate to any key, play dominant 7th chord from the new key you like to go to and you are there. Example: D major, than play Bb7 and than Eb-you are there.