How do you roll back what is the command?

How can one roll back I am stuck with the same problem and cannot find the option to roll back in the help

How can I move back to 17 and delete the other releases

+-------------+-----------+-------------+
| Name | Versions | Commit Hash |
+-------------+-----------+-------------+
| bss-ci | 0+dev.2 | e35126a4+ |
| | 0+dev.3 | e35126a4+ |
| | 0+dev.4 | e35126a4+ |
| | 0+dev.5 | e35126a4+ |
| | 0+dev.6 | e35126a4+ |
| | 0+dev.7 | e35126a4+ |
| | 0+dev.8 | e35126a4+ |
| | 0+dev.9 | 68b2c8f0 |
| | 0+dev.10 | d88752d2+ |
| | 0+dev.11 | d88752d2+ |
| | 0+dev.12 | d88752d2+ |
| | 0+dev.13 | d88752d2+ |
| | 0+dev.14 | d88752d2+ |
| | 0+dev.15 | 9eccdcfd |
| | 0+dev.16 | 9eccdcfd |
| | 0+dev.17* | 9eccdcfd+ |
| | 0+dev.18* | 9eccdcfd+ |
| | 0+dev.19* | 9eccdcfd+ |
| | 0+dev.20* | 9eccdcfd+ |
| | 0+dev.21* | 9eccdcfd+ |
+-------------+-----------+-------------+
(*) Currently deployed
(+) Uncommitted changes

Just update the manifest to use old release version e.g.

releases:
- name: bss-ci
version: 0+dev.17

...

and run bosh deploy again.