All depends on your standing orders. Any resolution can be visited ,amended or rescinded within the specified 6 month time period if it is the will of the PC. This would usually follow changed reasons or evidence not known or given for the resolution in the first place which may render the decision invalid.
The 6 month rule was designed to stop every resolution being continually challenged the minute they were made by those not in agreement with the decision made. But... not designed to "handcuff " the council to decisions made in error or with misinformation (or lack of) and to enable them to adapt to changing situations.