I would love the ability to have my customer service team edit an order within Shopify and share that information in Infoplus, so the warehouse can get real-time information.
Example: an order that has been processed in Shopify but not yet fulfilled by Infoplus may need an address change. We should be able to modify the shipping address and have it update the order in Infoplus.
* I'm an IP client, like you, not associated with IP
This is a super useful feature. Unfortunately, it's probably impossible to do technically. The issue is that Shopify and Infoplus are two different companies with two different servers. The relationship between the servers is asynchronous. Someone could change the order on Shopify at any time (same for the copy of the order on Infoplus). There always exists some scenario in which the changes made in one place don't make it to the other in time. Unless you slow allocation and fulfillment in Infoplus down to the speed at which you can check back with Shopify (not realistic) and that Shopify would allow you to make that many requests (not likely without significant fees), it's not possible to know whether you have the latest information for any given order with certainty.
Because changes are relatively rare, the best solution would be for some kind of plugin/module that confirms change acceptance. That is, Shopify would use the Infoplus API to ensure that something you changed in Shopify was changed in Infoplus... and Infoplus would ensure that something you changed in Infoplus was changed in Shopify. Unfortunately, both systems prevent changes to orders once they enter fulfillment so this isn't currently possible.
Hope that helps. If you know better, or I made a mistake, please let me know. We all want this! =)