Simplify the following text for a Grade 6 native English-speaking person.
Original: The following day , Germany invaded the Low Countries , and Chamberlain considered remaining in office . However , Attlee confirmed that Labor would not serve under Chamberlain , though it was willing to serve under someone else , and Chamberlain went to Buckingham Palace to resign and advise the King to send for Churchill .
Simplified: He spoke with Chamberlain , and soon Chamberlain began to agree with Churchill .