FAQ: My station is getting interference. Can we briefly change channels to "test" to see if a different channel is better?

No.

§73.875(c) of the FCC Rules specifies the types of changes that can be done without advance authorization from the FCC.  They include (with conditions in some cases):

• Replacement of an antenna with the one of the same type or different number of antenna bays provided that the height of the antenna radiation center is not more than 2 meters above or 4 meters below the authorized values.
• Replacement of a transmission line with one of a different type or length which changes the transmitter operating power (TPO) from the authorized value, but not the effective radiated power.
• Changes in time share hours pursuant to a new time share agreement. 

In these cases, a modification of license application (formerly Form 319) needs to be filed within 10 days of making the change.

§73.875(b)(4) specifically forbids a channel change without first receiving a granted construction permit. 

Channel changes, even brief ones without an appropriate instrument of authorization (i.e. a construction permit) would be construed as unauthorized operation in violation of Section 301 of the Communications Act and is subject to a potential $10,000 forfeiture.  

It's also important to remember that the other channel may not meet the minimum distance separation requirements of §73.807 and a permanent channel change may not be possible.  It may also be possible that the new channel may require an interference showing in the event that the channel does not meet the minimum distance separation requirements for second-adjacent channels.  The Local Community Radio Act of 2010 requires that distance separation be used to protect all full-service stations on co-channel, first- and second-adjacent channels (with waivers available for second-adjacent).  If you need assistance with interference or need to make a channel change, please contact REC Networks at 202 621-2355.

If granted a construction permit, then the station can "test" on the other channel.  If it turns out that the other channel will not work out better, then the LPFM station should request cancellation of the modification construction permit and revert operations back to their originally authorized channel and facility.  If it turns out the channel change will work out better, please do not forget to file a License to Cover to advise the FCC that the change has been made.  LPFM stations cannot operate on both their old and new facilities simultaneously.  

Also note, that a construction permit has a 3-year term attached to it.  If operations continue on the new facility and no License to Cover is ever filed and the period of construction lapses, continued operation on the new facility is considered unauthorized operation and is subject to a forfeiture.