Hello @Kiran-Kishore,
I’ve been facing a very similar issue this week but I didn’t find it in here (UiPath Forum). So I just got the solution through testing and more testing. Just clarifying my understanding about your case. You have a Main WF and it runs SEQ1, takes a value from there and brings it to Main, then your Main runs SEQ2 but the value needs to go from Main to SEQ2. Is that right?
So, what you need to do is pretty simple: Create an Argument in SEQ2, the Direction must be “IN”. Inside Main, when you use the Invoke activity to run SEQ2, click on its button “Import Arguments”, select the Argument you created in SEQ2, select the Direction as “IN” if it is not already, then in Value, set your variable in Main that contains the information from SEQ1.
You can take a look on my example below. Hope it may help you and any other like us 
ExportArguments.zip (3.5 KB)