Yes...we move shelves often, but there are some considerations...others will likely give other considerations I forgot to mention.
There is no HOT removal of shelves. So the 2020 needs to be shut down prior to removal. But you can hot add to the 2050.
Make sure you have free FC ports ont he 2050 (has to be a DS14 shelf since it is a 2020)
Make sure the ONTAP versions are the same major release on the 2020/2050... for example if the 2050 is on 7.2.5 and the 2020 is on 7.3.4, then the shelf won't come up on the 2050... vice-versa would be ok.. the raid labels change between major releases.
Make sure that the 2020 isn't relying on this disk shelf...for example, if the root aggregate is on this shelf...
If you want to add as new disks, usually make sure all disks are spares, make sure they are zeroed, then disk remove_ownership on the disks from advanced mode...even though you can reassign on the 2050, it is easier if there is no ownership on the disks...in some cases we have to go to maintenance mode on the system it is installed on (shouldn't have to, but just in case remove ownership prior to removing the shelf from the 2020).
If you are moving existing data...do a full backup first... then when you attach and assign to the 2050, I prefer to make sure I can online the aggregate from maintenance mode...although if no downtime on the 2050 is allowed you can hot add, assign then bring the aggr online...but do a full backup just in case..
Work with your NetApp/VAR team on moving the shelf since there may be maintenance/support implications..