Is it possible to create widget out of GameThread?

when I remove a widget in callback function of TCP receive thread which handles all message received from server-side, my project crashed with error:

Assertion failed: IsInGameThread() [File:D:\BuildFarm\buildmachine_++UE4+Release-4.11\Engine\Source\Runtime\Slate\Public\Framework\Application\SlateApplication.h] [Line: 156]

is it possible to handle widget out of GameThread? or how can I delegate my task to GameThread? Tick() function is a solution to check messages what are received from other threads, but I think it isn’t effective.