I read somewhere you could because he's only guaranteed 1mil and he signed his contract under the old CBA.

The non-guaranteed contracts

Veteran Lance Thomas is the key to New York getting to the $70 million number. Signed to a four-year, $27.5 million contract in 2016, Thomas has a June 30 guarantee date for $1 million of his $7.6 million contract. If Thomas is waived, New York would have $72.5 million in room, enough for a double max slot.

There is a scenario for Thomas to be on the roster past June 30 with New York still having the double max slot available. Because the Thomas contract is guaranteed for only $1 million past June 30, New York can keep the forward and decide at a later date if there is a need to stretch his $1 million over three seasons ($333,000 cap hit).

The contract of Thomas also has value if New York does not waive him. Because the forward signed his contract in 2016 under the previous collective bargaining agreement, the NBA allows the full $7.6 million cap hit to be used in a trade (rather than just the guaranteed amount).