Exegesis:

luontōn de autōn ton pōlon ‘as they were untying the colt,’ describing the situation as presumed by Jesus, cf. on v. 31.

hoi kurioi autou ‘its owners,’ cf. on 1.6 (1).

(V. 34) hoti cf. on v. 31.

Translation:

The first part of v. 33 may be rendered better as two coordinated sentences, e.g. ‘they untied (or, began to untie) the colt, but then the owners said to them.’

(V. 34) The Lord has need of it. The disciples now actually say what in v. 31 Jesus told them to say; the discourse structure is one degree less intricate. The wording should echo v. 31d as closely as possible.

Quoted with permission from Reiling, J. and Swellengrebel, J.L. A Handbook on the Gospel of Luke. (UBS Handbook Series). New York: UBS, 1971. For this and other handbooks for translators see here . Make sure to also consult the Handbook on the Gospel of Mark for parallel or similar verses.