When someone says shape up or ship out it is used as an ultimatum to improve their performance or behaviour.
Used as a command to improve one’s performance or leave.
A warning to say improve or get out.
1. This is the last time I’ll tell you. Shape up or ship out!
2. This last project was your biggest mistake. You’d better shape up or ship out.
3. Nathan was late again, so I told him to shape up or ship out.
4. I heard the committee is going to make the coach shape up or ship out.
amend, change one’s ways, clean up, clean up one’s act, convert, correct, improve, rearrange, rebuild, rehabilitate, remake, renovate, reorganize, repair, resolve, restore, revise, transform