Declaring an emergency doesn't shift one into some parallel dimension where things have suddenly changed. You're simply stated that you have a problem and that you need help.
If you no longer have the problem, say so, and move on. You're pilot in command. State your intentions and be done with it.
I think sometimes people have this bizarre image in their heads that "declaring" an emergency sets a mystical chain of events in motion, causes all the lights to turn red and claxons to sound at the nearest ATC facility, and the FAA to go on high alert.
You simply state what you have, and what you intend to do.
By example, we got a fire light coming out of FAT in a C-130 once. We knew the propensity of that airplane to give false fire indications, and we spent a few minutes sorting it out to the east of the airport. We advised ATC what we had, then resolved it, and then advised them we were continuing with our mission. End of story. Not another word said, no problem, no muss, no fuss. Typical.
We probably wouldn't have said anything at all, but the false indications were typically sunlight or reflection from the ground setting off the warning, and usually a 90 degree turn or two would make it go away. ATC wanted to know about our turns, we told them, and we made it go away. They asked if we needed trucks, we said no, and went to the fire.