I have the following workflow in my application:
In the first comment, @Hans gave the correct link to the similar topic. However, if it doesnt help, then here is solution:
just add &prompt=consent
parameter in requesting google's url.
I think you can add some parameter in the url to tell google to show the consent screen with the user accounts instead of assuming the default google account.
This can be done by adding prompt=select_account+consent
("+" is added as a part of url encoding) in the url.
I did not try this till now but maybe you can try.