A sponsor and project manager found out that a vendor in a different time zone...

 The project manager should communicate individually with the affected team members to negotiate the decision and confirm their willingness to relocate, as this is the most respectful and ethical way to handle the situation. Relocating team members abroad for six months is a major change that will affect their personal and professional lives, and the project manager should consider their needs, preferences, and concerns before making any final decisions. The project manager should also explain the rationale and benefits of the relocation, and offer any support or incentives that may facilitate the transition. Communicating to the whole team, the HR department, or the team members’ manager may not be appropriate or sufficient, as the project manager should first consult with the team members directly and obtain their consent. These other communication options may also create unnecessary confusion, resentment, or resistance among the team members or other stakeholders. References: PMBOK Guide, 7th edition, pages 111, 112, 113, 114.