Editor's note: Inc.com columnist Alison Green answers questions about workplace and management issues--everything from how to deal with a micromanaging boss to how to talk to someone on your team about body odor.

A reader writes:

My colleague and I work in a particularly specialized area in our firm. There are the two of us, plus our director, who is not a specialist.

My colleague, Mary, recently returned from having her second child and asked to work 10 a.m. to 3 p.m., five days a week, which she got. So she's down to 60 percent of standard hours. She is out the door on the dot at 3, and as far as I know, she is not doing any work in the evenings--some client materials cannot leave the office, but she also does not seem to be answering any emails or doing any online research.

Good for her, you might say--but the problem I have with this is the staff of my mini department is down from 2 to effectively 1.6. The work coming in has not decreased at all. I have all my existing clients to work on, plus those of Mary's who phone with urgent queries after she has gone, all clients for whom some travel is required (including several who used to be Mary's), and most of the new inquiries, since I am the person who is in the office at the end and at the beginning of the day. My office hours are 9 to 5:30, and before Mary went part time, 85 percent of the year I would be out of the office by 6. Now? I'm working lunch and leaving by 8 at the earliest, plus my travel has doubled.

I find myself becoming increasingly irritated at Mary for assuming that she can leave on time and that I will just deal with work that comes up when she is gone for the day. I have said to her on more than one occasion, "Look, I cannot do this for you. I have xyz of my own to finish," to be met with either "But my hours are shorter now" or "But if it does not get done, we will lose the client." And unfortunately, if the clients dry up, so does the job.

I am even more irritated at my employer, who agreed to Mary's working part time without considering that that meant I would be doing not only my job but also half of Mary's. My director tells me that he made the point that neither he nor I saw this as a workable solution, but apparently the head and HR wanted the firm to appear to be family friendly. Both of us have asked whether in that case we can have another part timer, which has been met with baffled looks.

I used to really enjoy my job, but this cannot continue. I have already registered with a couple of recruitment agencies. Do you have any other suggestions?

First, try not to be irritated with Mary. While on the surface, she's the one who put you in this position, the reality is that it's your employer who put you in this position, by agreeing to reduce your team's resources without making any adjustments to accommodate that. Mary asked for something reasonable; your employer is the one who then dropped the ball.

Second, you need to say this to your manager: "We have lost 20 percent of our manpower, and all the burden of making up for that is falling on me. I am trying to serve my own clients, while also juggling inquiries from Mary's clients during the hours she's not here, plus additional travel that she's not doing anymore. Since Mary went part time, my own hours have increased by an average of X percent, and my travel has doubled. I am glad that the company is trying to be family friendly, but as a result of accommodating Mary's new schedule, I am earning the same salary for significantly more work and a doubled travel burden. This is not sustainable."

Your manager then probably needs to say a version of this to his own manager, hopefully pointing out that if you leave and they have to replace you, the department will be handling even less work while the new person learns the ropes. And your manager needs to really push on this issue--it's his job to push for what the department needs to function smoothly, and to explain it in a way that won't produce baffled looks (i.e., explaining that neither of you see it as a workable solution isn't enough; he needs to show them exactly why).

If nothing changes and you do end up job hunting as a result, you could explain it to prospective employers by saying something like, "My manager would be the first to tell you that a departmental reorganization has left us without the resources to work as well as we used to be able to. I completely understand shifting resources and I've given it some time to shake out, but at this point I've decided to see what options are out there."

Want to submit a question of your own? Send it to alison@askamanager.org.