You can use search shortcuts to quickly find your reservations, in Reservations > Search Mode 

For example, if you type in mar11 it will auto-expand it to search for Mar0011-20

"the 11th reservation in March, in the current year."

If you need to search in other years you will still need to type in the full reservation reference:

Mar0011-21 or Mar0011-19

Please also ensure your date ranges are correct if you're searching outside of the current year.

some other valid examples (assuming the current year = 2020)

Jan1 > Jan0001-20

Sep150 > Sep0150-20

Nov99 > Nov0099-20