I’m still using HS4 right now and hope to upgrade soon and I don’t know if there is a trick I can use with HS4. I need to extend the length of an analog sound. I have a scream that is perfect for my song but the scream ends too soon. I don’t have a way to reproduce it. Is there a way to expand the last few seconds of the scream?

You could try several things.  The first I'd try would be a delay with a very short delay time and a substantial amount of feedback.  You'd also probably need to automate the level to get the continued sound to start and to die out at the desired time.  You could also try a very wet plate reverb.  If you have Valhala Plate, that might do it nicely.  Again, automation is your friend.

ok, thanks, I will try these options.

I've been faced with that exact same scenario. I had a thick four-part harmony singing an "AH" that ended a song, but was about 1.5 seconds too short. No way I was going to re-record four vocal tracks just to stretch that final note.
 
Try this...duplicate the clip in another track and use slip-edits to trim the dupe down so it contains no identifiable transients. Then split the original clip, slide the two halves apart and insert your duplicated clip between them. Slip-edits should be able to make them merge seamlessly, although it'll probably require some trial-and-error.
 
As a final coating of spackle to further hide the seams, apply a thick hall reverb. This can be automated so it only comes in when needed.
 

I ended up using some of both techniques in a around about way. Delay was no help for me. I used my IK CSR Plate then bounced it and put the plate on the bounced track, front fade to the extended part, then slide the bounced track until it fit. Now it fades out great! I thank you both!

bitflipper
I've been faced with that exact same scenario. I had a thick four-part harmony singing an "AH" that ended a song, but was about 1.5 seconds too short. No way I was going to re-record four vocal tracks just to stretch that final note.
 
Try this...duplicate the clip in another track and use slip-edits to trim the dupe down so it contains no identifiable transients. Then split the original clip, slide the two halves apart and insert your duplicated clip between them. Slip-edits should be able to make them merge seamlessly, although it'll probably require some trial-and-error.
 
As a final coating of spackle to further hide the seams, apply a thick hall reverb. This can be automated so it only comes in when needed.
 

Why, Dave ... I think you've just invented granular synthesis.