SD 16600 date change problem

[Sarajevo]

I have an M series SD 16600. I bought it new in October 2007.

Upon returning from a recent trip where I did not bring it, I needed to change the date. As most here will know, per the Rolex Oyster manual, it is the third action with the crown, i.e. before the time change. However, I cannot change the date - the crown goes from the winding position to the time change position. I have tried this numerous times, and used a reasonable amount of force. I have not tried too hard to pull, for obvious reasons.

The watch has been treated well and has not been dropped, etc. It is worn on alternate days in rotation with an IWC 371701.

I was planning on getting it serviced anyway and this issue has brought that forward.

Has anyone here had a similar issue?
If so, do you know if this can be fixed via a regular service or is it a more fundamental problem.

Any tips welcome to help an anxious SD owner