Using Forms to Execute API to Call Other Application

Summary:

Hi. Can we use FORMS to execute an API to call another application (e.g. C2M) to request validation (e.g. If new meter is already installed on other premises) and receive this validation result back to the FORMS to create a warning message? Then user can click either Continue or Cancel?

If yes, is there an example document. And if none, any suggestion where I can create a plug-in dialog box?

Currently, there's a Device Validation plug-in but I cannot extend/update the dialog box to add more fields so I am trying to see if I can create my own dialog box from OFS itself.