Under the terms of your shared ownership agreement lease agreement, you will likely not be allowed to sublet the property.
If you are found to be doing this you may be evicted from the property and have to deal with any of the consequences that arise due to this decision.
Subletting essentially means entering into a rental agreement to let out a property. If you sublet your shared ownership property you will likely be breaking a covenant in your lease agreement
Unfortunately, in most cases there are just no alternatives but following the terms of your lease agreement.
Imagine you are purchasing another property but you do not want to continue paying rent and the mortgage of your shared ownership. You will either have to sell your shared ownership property or staircase to 100% of the shares in the property
This is the case regardless of what the scenario is.
The final option will, of course, be to get written permission from your landlord(Housing association) that you can sublet your property and for how long.