My small team covers areas A, B and C. A is our main area. We recruited to cover C specifically, about 3 years ago as this was a growing area. The person covering C fits in some non-time-critical work on A as and when they can, which to come extent makes up for the fact that when the person doing C is off, another team member has to cover. This isn't very popular as it takes other team members away from their own tasks. (I hope you are following!)
Now another team lead has made a pitch to take over C. You'd think I'd be biting their hand off. However. The other team lead is already a higher grade than me and has a smaller team. There seems to be some concern that her role isn't 'strong' enough for her grade, which is why she wants to take C out of my remit. My role was recently reviewed and wasn't considered 'strong' enough for it to be upgraded. The 'C' part of my remit in no way maps on to the higher grade. The plan by the other team lead - and her line manager! - is that if she takes on C it will strengthen her role as the higher grade.
So, do I dig my heels in and keep C, or cheerfully hand C over to her? I've struggled for years to be upgraded, without success. She was upgraded after failing to be appointed to a specific, higher-grade, role because her line manager effectively invented a role for her: our new boss now has her higher-grade role scrutiny so she's trying to 'strengthen' it by taking part of my role away from me.
What would you do?