I've seen various lists of reasons for issuing change orders on a project. Is there a standard in either the Architect's Act orthe CCDC series which is universally accepted?
Short answer is NO.
Reasons that I am aware of have no status in legislation, regulation or practice and there is always variance in form and language from province to province and office to office. However, the common threads are:
A response to
Site Conditions
Emergency Situations
Scope Change
In describing a change one might use the Journalists 5Ws approach. Why, Who, Where, When, and What.
If the above is Why, then next is Who.
Requested by
Parties to the Contract
Sub Trades
Sub Consultants
Authorities Having Jurisdiction
Where, can written in long form or codified for physical location of change, like Second Floor, West Elevation, Mechanical Room 35, etc.
When, can be tied to a calendar date or schedule.
And finally, What is usually the description of the change Work itself.
Of course all of these descriptions can get reviewed and later interpreted by others to mean something else entirely, but the simpler the process the harder it is to distort the meaning.
You may wish to refrain from assigning a reason to Change Orders for potential liability reasons.