Depends on (one's) circumstances; subject to how things work out or someone's convenience.
ミーティングの開始時間は都合次第で変更できます。
The meeting start time can be changed depending on circumstances.
参加の可否は都合次第なので、無理しないでください。
Whether you can attend depends on your situation, so don't push yourself.
経営陣の都合次第でプロジェクトの方針が変わった。
The project's policy changed according to the management's convenience/circumstances.