Our streetside, full length awning had a torn pull-down strap when we got it (Zip Dee brand). Make sure all of the lock-downs are off (ours has one at each end that turn to loosen and then flip off the arm to unlock). Then you and another person should be able to pull on each arm to get the awning to come out. As it comes out, it will get easier to pull on. Once out, you may see a torn off piece of the strap hanging or the plate where the strap used to attach.
We took a piece of nylon belting and made a new strap and using rivets, reattach to the tube and it has been working well.
If it is a Zip Dee awning, their customer support is really helpful as well.
Tadd, Beth, Grundgetta and Weeble
Proud to be Air #37137