Resume suspended process instance

I have an instance of process which fails on error. I want to resume the process from some other activity (by REST). I call /process-instance/${processInstanceId}/modification with activity name and modified variables. But I’m not able to do it because the call fails on process suspended exception. I can call /process-instance/${processInstanceId}/suspended with value of false first. But the whole process (unsuspend and modification) are two task (two calls). So it could happen something in between. Is there any oter way how to accomplish this?