I have my main sequence. And within that sequence is yet another sequence (i will call that SEQ_1). SEQ_1 is original 5 seconds and is placed in my timeline. If i open SEQ_1 and change the time to say 3 seconds how do i update SEQ_1 in my main time line to match the new time of 3 seconds. Or must i delete it and then reinsert it?
Shorten it the way you would any other clip.
You will notice the diagnal lines on the sequence acting as a clip in the other sequence. That indicates that it has been shortened and needs your attention.