To want my colleague to allow my employee to prioritise some work for me?

[Rocas]

not sure if IABU,so please give me your honest thoughts on this.
My department at work is being restructured and during this time my staff are being loaned to other depts.Staff are requested either through me or my line manager and we allocate them to the depts most in need.
During this period my dept still pays for my staff,the other depts are basically getting extra staffing for free,this I feel is particularly relevant.
I have sent an employee to work in a particular dept after a request from my colleague for specific shifts,I informed my employee who was happy to go there.Once there the dept manager changed all the shift times-not a problem as both myself and employee were ok with that.
During this restructure my employee has been working on a new business account that will benefit my dept,they have requested a meeting that clashes with a shift.
The dept manager will not allow my employee to reschedule despite this meaning we may lose this contact.As I previously stated my employee is an extra person and free for him,so I feel that he doesn't have the right to do this.Long term this contact could prove to be beneficial for the company,not just my dept.
So,am I BU to say to my colleague that I need him to allow my employee to either leave early or rearrange their shift?

Not at all. Perhaps talk to your manager. Maybe the other departments need some clarification on the issue!

Thanks Hecate,I didn't want to create a difficult situation with him ad this is the second staff related issue I have had with him.Tbh it's more around what I find acceptable practice with staff in terms of contact etc and I have already had words with him about this.
I emailed him and clearly but politely said that he needed to release my employee as it was a potential client we could lose.
Waiting for a reply,will speak to my line manager if it's still an issue

The other manager obviously needs your person to cover their shift, and they can't/won't see the bigger picture. A new contract comes before everything in this day and age (IMO!). You definitely need to raise it with either your own manager or the other manager's manager.

Yes I agree Wilson!we share the same line manager,I wanted to get other opinions on this b4 I spoke to them.
I don't want to be seen to be telling tales but I'm not happy at the management of my employees in certain areas,I have expressly stayed this as well.

*stated this

I'm getting totally confuddled here

Are you talking about your 'employee' as in a person who you actually employ yourself to work for you?

Or are you talking about staff who are employed by the company you work for?

I am a manager of 30 employees,my colleague in another dept is another manager of about 10 employees.myself and my colleague share the same line manager,we work for a logistics company.
Sorry if it was confusing!

No I've got it now thanks!

Some people refer to their staff as their employees (even though they're not really) and some people refer to them as staff.

But YANBU anyway, it sounds like bad management on behalf of your colleague.