go it alone

He quit working for the company and decided to go it alone as a consultant instead.

When the trump suit [in euchre] has been settled, the player who has named it (the maker) has the right to go it alone, but he must announce his intention to do so before a card has been led. His partner places his cards face downwards on the table, and takes no active part in the hand. The maker (he is the only one of the four who can go it alone) plays his hand against the two opponents in partnership.