How do you change an exit name? Traveling I-5 South to Downtown Seattle, it tells me to take the 6th St Exit and that doesn’t exist. It should be the James St exit. This caused me to travel 2 miles to the next exit and get off on Dearborn St.
There is no southbound exit mapped onto James Street. The nearest is http://www.openstreetmap.org/node/1115816511 which is onto 6th Avenue, so it seems not unreasonable for the software to call it the 6th Avenue exit.
It is certainly possible to name motorway (UK English) junctions. I presume the junction would be www.openstreetmap.org/node/1115816560 which has ref=165A.
It does seem that the the first segment of the slip road http://www.openstreetmap.org/way/96260967 is tagged as destination=James Street, which is probably the best that can be done within the OSM tagging system and what is actually on the ground.
I’d therefore suggest that the combination of the preparation software and the routing software should have been able to say “turn off towards James Street at junction 165A”, and it if is failing to do so you should raise it as a bug report or feature request, with the authors of that software. However, the destination tag was only added three months ago, so you may simply be using out of date data.
I think I would have continued the destination tag along the whole length of the slip road.
Please note that you have not told us what “it” is.